Tag Archives: backyard chickens

Why aren’t there more Chicken Vets?

I have been asked numerous times why there are no vets around who work on backyard chickens.  It’s been suggested that I should specialize in backyard health and make my millions.  There has been an article in the Wall Street Journal no less, decrying the lack of vets with chicken experience (http://online.wsj.com/article/SB10001424127887323527004579081812563033586.html?mod=WSJ_hp_EditorsPicks#articleTabs%3Darticle). 

I will try to tell you why there is a lack of vet care available for your chickens.  Like most real-life problems, it is complicated, involves money, attitudes, history and inertia.  Some ways to approach providing backyarders access to vet care include a backyard poultry only practice, professional poultry vets branching out into backyard flocks, or small animal vets branching out into backyard flocks.  All of these have challenges.  I will give you my top 10 reasons why there is a lack of veterinary care for backyard flocks;

     10) Money

I have worked exclusively with poultry for 15 years now.  I’m happy with my income (unless you happen to be my boss, in which case, I’d like a raise), and I like working with the birds.  I visit about 2 – 3 flocks per day, and I earn hundreds of dollars from each visit (sue me, but I’d like to earn more than a plumber….10 years of post-secondary education left me with a small mortgage, and it should be worth SOMETHING).  Since the flocks I visit have thousands of birds, each visit costs pennies per hen.  Many backyarders won’t be willing to pay $50+ per visit, which is about the minimum I’d need to keep my doors open.

      9) Biosecurity

 I know activists would have you believe that biosecurity is just an excuse to keep professional farms out of the public’s eye, but it is a crucial component of the health programs on all commercial sized farms.   This year alone, I am aware of backyard flocks who have been diagnosed with Avian Influenza, Mycoplasma, Salmonella enteritidis, Infectious Laryingotracheitis, Fowl Cholera and Blackhead…..all of which would be devastating in a professional flock…..as in, people losing their livelihood and home, level of devastation.  Believe it or not, the amount and variety of diseases in backyard flocks dwarf the infections on professional farms, and the risk of carrying diseases is very real.

    8) Liability

I have been asked to do things like prescribe medications or sign export certificates on backyard flocks.  The reality is that, as a professional, every time I sign my name to a certificate, it is on me to make SURE it is true.  So, if you want to move a flock across state lines, and I sign a form saying your flock has shown no signs of disease X in the past 3 months, I need to be SURE that they haven’t.  This means that I need to know you and your flock well, and have multiple visits (costing you $$ multiple times).  If the hens are carrying the disease I stated they were free of, it is ME who is charged with negligence or malpractice.  This is not as big an issue for small animal vets, because the impact of a missed case of kennel cough or FELV isn’t the same as moving the hens that are the start of an agricultural disease (the Avian Influenza outbreak in British Columbia cost an estimated $380 million, and almost definitely started in a backyard duck flock). 

     7) Different type of Medicine

For me, as a commercial vet, I concentrate on keeping flocks healthy.  To do that I do what is called “population medicine”, and am more focussed on the health of the group as opposed to each individual hen.  Sick hens will often be euthanized to be examined and samples taken so the rest of the flock can be appropriately treated.  That model does not work for backyard flocks.  Techniques like exploratory surgery, intravenous fluids, severe wound repair or life support therapy are necessary, even crucial when dealing with backyard hens, but I am not used to performing them, and it is an entirely different mindset.

    6) Interest

Very few small animal vets have any experience or interest in chickens.  They like dogs and cats, and think guinea pigs and hedgehogs are cute, but chickens are alien to almost all of them.  Chickens are so different than the mammalian patients my classmates see that they are very uncomfortable in even attempting to deal with them.  This is a wide generalization, but holds true in most cases.  I know of an injured hen that was flatly refused at a vet clinic because the vet said she “wouldn’t even know where to start”.

     5) Lack of tools

Chickens are no longer expected to be in small groups in North America.  Vaccines come in bottles of 1000, 5000, 10,000 or 25,000 doses, and once opened, need to be used within 2 hours or they don’t work.  (One of the vaccines I use can only be bought in a 25,000 dose bottle).  Even though I want to recommend vaccination of backyard flocks, it is difficult to justify buying 5000 doses of Newcastle Disease vaccine for your 5 hens.  Antibiotics are the same….most come in a pouch that treats 100 gallons of water….once opened, the antibiotic starts to lose efficacy, and should not be stored for later use.

     4) Lack of Numbers

Even if there was a way to provide decent care in a metropolis like Toronto, or New York, that would still only help a very small percentage of the backyard hens…..what about the smaller cities, towns, and even rural flocks (cow and horse vets don’t really have any comfort with chickens either, as a rule).  Unless there is a critical mass of hens, it is very difficult to provide care, regardless of the location.

     3) Chickens are weird

Face it…chickens are weird.  They have an odd social structure that can seriously impact their health, they have a wildly different biology that other pet animals (respiratory, digestive, reproductive, cardiovascular, immune, bone and skin systems are all vastly different than other pets).  It means that a small animal vet cannot apply what he/she knows in other areas to the chicken.  A chinchilla is not that different that a dog or cat, and you can logically adapt treatments if one is brought into your clinic, but a chicken does not fit the model.  At all.

     2) Chickens are food

Another aspect of treating chickens that makes small animal vets uncomfortable is that you don’t (usually) eat your pets.  I am very aware of the human health implications of everything I do on a farm.  I only use antibiotics that I am confident will not contaminate the eggs or meat, or else I know how long that contamination will persist for, and advise against eating the eggs for a period of time.  Small animal vets don’t have this background, and are (rightly) worried about causing residues that make people sick.

    1) Inertia

The number one reason that vet care isn’t more available for backyard chickens is inertia.  “It just isn’t done”.  Like giving women the vote, this is unheard of, and might be the end of civilization as we know it.  Keep asking your vet (and other vets) to look after your hens.  Be willing to pay a little, in order to make him/her think about making it a part of the clinic’s business model.  Be patient if they are slow, or unsure.  Keep trying to make it happen, and in the near future, someone will figure out that treating chickens is not scary or dangerous, and a model for this type of medicine will emerge and become commonplace. 

 

Mike the Chicken Vet

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Chicken Lungs

Anyone who knows me knows of my hate-hate relationship with running.  I have started running in the past year, and have decided that it is the most ridiculous activity known to man.  You can’t score goals, you can’t look cool, and you will NEVER make it to Sportcenter (Usain Bolt excluded….I mean….he IS Usain Bolt).

The main reason I hate running is because I suck at it.  I’m strong, but my aerobic capacity is lousy.  I wish I was a bird.  If I was a bird, my trachea (windpipe) would be 2.7 times as large, reducing air resistance.  My rate of breathing would be about 1/3 of what it is currently, and I would take much bigger breaths.  This is the first part of the system that makes the bird respiratory system much more efficient at gas exchange than mammals (especially this particular mammal).

chicken airsacs

Location of Air Sacs in a hen

Chickens also have structures called air sacs.  The way to think of them are a bit like bagpipes…..they act as reservoirs for air so that there is constantly fresh air passing through the hens lungs.  A bird’s respiratory cycle is much more complicated than ours….we inhale into a big, complicated balloon, pause, and then push the air out.  As the air sits in the tiny air sacs (called alveoli), oxygen diffuses into the blood, and CO2 diffuses out.   Our alveoli are like a bunch of grapes….blind ended sacs that expand and contract as air comes in and out.  During the pause between breaths, the oxygen concentrations of the gasses change, and diffusion becomes slower. In hens, it goes like this….INHALE – air goes into the lungs and the abdominal air sacs.  EXHALE – air leaves the cranial, clavicular and cervical air sacs.  PAUSE – air goes from lungs to front air sacs while air is travelling from abdominal air sacs to the lungs.  Repeat as necessary.The result of these airbags is that there is a constant, one way flow through the lungs, and every part of the lung is constantly filled with fresh, fully oxygenated air.  Chickens have no alveoli…they have a network of tiny tubes where the air never stops flowing.

Diagram of airflow....not simple, but effecive

Diagram of airflow….not simple, but effecive

Hens have other adaptations too.  Birds have hollow bones, and the front air sacs communicate with the wing bones and the clavicles.  Thus, chickens even use their bones to breathe!  At the microscopic level, the point at which the oxygen enters the blood (and CO2 leaves it) is different too.  Cross current exchange where blood travels at 90 degrees to the airflow in the tiny lung tubes….makes for much more efficient exchange because the same air crosses blood vessels several times, instead of just once as in us mammals.  Also, the thickness of the tissues between the blood and the air is less than half that in mammals of similar sizes.Chickens have no diaphragm, which is the muscle we use to expand our chest cavity downwards.  This has major implications if you are handling chickens, especially small ones.  Their keel bone (Breast bone) MUST be able to move, or they can’t inhale.  Holding or wrapping a chicken  too tightly will stop her from breathing.  This is really important when children are around the hens, since a hug that would work for Fido will not work for chickens.So, in summary…birds breathe slower, deeper and more efficiently.  They have one way flow of air through their lungs through the adaptation of air sacs that act as bellows to constantly supply fresh air to the blood, even when the hen is not inhaling.This is why birds have such an efficient respiratory system, and why aerobic exercise is so much easier for them.When I am about 2 miles into a run, I really hate chickens. Mike the Chicken Vet

Chicken Guts

As promised, I am starting a description of the different systems inside the modern chicken.  I thought I’d start with a description of the intestinal tract of a hen. From beak to butt, there are a lot of specializations that allow chickens to magically convert grubs, worms, corn, grains and calcium into eggs…one of the most nutritionally dense foodstuffs in nature.

Not a pretty picture, but shows the tongue and choanal slit well

First off, it is always amazing to me that people are surprised to find that chickens have triangular tongues. What other shape could it be? There is also a slit (called a choanal slit) in the roof of the top beak. It is here that many substances that are eaten and drank are exposed to the immune system. The triangular tongue is very poor at sensing taste. The human tongue has about 10,000 taste buds, cows have about 20,000, and chickens have 25. Not 25,000….25. Chickens, like most birds, rely heavily on their eyes to locate food, and don’t invest a lot of brain space to taste. It explains some of the things they are willing to eat!!  You will also notice the scarcity of teeth. (Yes, your grandmother was right….hens teeth ARE rare).   More on this later.

After the food passes through the beak mostly untasted, it passes through the esophagus, a 3″ muscular tube, until it is deposited into the crop.  The crop is basically a holding tank for food and water.  It is muscular, but weak.  If a Anatomy-of-the-chicken-with-text

chicken eats things that are difficult to pass through the crop (like long blades of grass or hay), or the stuff in the crop gets too dried out, you get impacted crops.  If the contents stay there too long and start to rot, sour crop can result.  To help with either of these problems, it is important first to get the offending material out of the crop, and allow the muscles to relax, and the interior of the crop to become normal.

I know, its gross, but I’m a vet…this is what I do. Plus it gives you a good idea how things really look.

The the food is now the consistency of gruel and enters the proventriculus.  This stomach is similar to ours.  It secretes acids and enzymes and starts actively breaking down the food.  The food now enters the gizzard, which is a very muscular organ that is lined with a tough substance called koilin.  Inside the gizzard, the hen stores small pebbles.  These pebbles get rolled around inside the gizzard through the muscular contractions, and the action is like a grist mill.  Remember the part about the lack of teeth?  This is the compensation.  Stones are lighter than teeth, because you don’t need too many of them, since the feed is already pre-softened by soaking in the crop.  In professional farms, the stones are provided as pieces of oyster shell or limestone, both of which also act as a source of calcium for egg-shell and bone strength.

Once through the gizzard, the gut contents are like a very moist paste, very uniform, and still smelling like chicken feed.  It enters the small intestine, where the pancreas and the gall bladder add their contributions of enzymes and bile acids respectively.  The food is now basically reduced into its components.  For the next 30 cm or so, the protein, fats, sugars and other nutrients are absorbed into the bloodstream.  This is the function of the small intestine.  You can imagine, if there is some problem with the intestine, absorption will be reduced, and the volume of manure will increase…..this is the root cause of many cases of diarrhea.  The gut contents are now a darker brown, and more dense and pasty…pretty much half-way between feed and poo.

The food now enters the two cecums (called cecae when plura….great word to remember for Scrabble).  The primary functions of the cecae are to absorb

Normal Cecal Dropping
Normal Cecal Dropping
normal dropping

Normal Dropping

water and to act as an immune organ.   The contents of these are fairly light….lighter than normal chicken poo.  Every couple of days, the cecae empty themselves, resulting in a cecal dropping, which is sticky, somewhat foamy, and lighter in colour.  These droppings are very distinct, and completely normal.  It also explains why anything that stimulates the immune system can result in diarrhea, since the same organ is responsible for water resorption from the gut contents.The final step in this process is the ejection of the manure (sometimes with a fair bit of velocity!).  The interesting part of this is that birds have “vents”.  That means that the urinary tract, reproductive tract and gastrointestinal tract all leave the body through the same orifice.  Meaning, everything comes out of the same hole…..sometimes at the same time.  That is why the normal manure has the white, uric acid cap on it…that is the bird’s version of urine.  Importantly, it is also a source of manure contamination of eggs, especially if the hens are sick and have loose manure.  I have talked about safe egg handling previously, but I would like to re-emphasize the importance of this.

All in all, it takes around 3 hours for a piece of chicken feed to become chicken manure.  For humans, gut passage time is around 2 days. This speedy transit time is important for….wait for it…..flight.  Birds will actually spend a fair bit of time with almost nothing in their guts….thus lighter and more able to fly.  But, this short passage time means that diets that are high in indigestible components will seriously increase the fecal volume, since there isn’t time to break down the more fibrous bits.

So, that is the story of  chicken feed becoming raw materials for eggs and the necessary body processes that support the chicken in everything she does.  Remember that bird digestion is quite different from mammalian digestion, and some of the gut problems you might see in a small (or large) flock will show certain symptoms because of the way the gut works.

Mike the Chicken Vet

What makes a chicken?

I am starting  a short series of posts that will describe some of the physiology, anatomy, and behaviour of the modern chicken.  This has been done many times before, by people more qualified than I am….in greater detail….likely more accurately….and with far more authority.  They are called textbooks.

The difference is, I am going to make it interesting, useful, and hopefully fun.  Oh, and it will be in the english that normal humans speak.  I also intend to explain some of the reasons why chickens are the way they are….how some of the attributes of “chicken-ness” are useful for the birds.  The aim of the series is to give the readers some tools to problem solve issues that may crop up in their flock (pardon the pun…..see, entertaining all ready!).  If you know how the guts of a hen works, you have an idea as to what might be going wrong when you see diarrhea or blood in the droppings.  At the very least, it will give you another way to think about the way a hen works.

To start, I will talk about some of the striking factors that make chickens the way they are, and why they are that way.

Birds are strange creatures….feathers, eggs, hollow bones, no teeth, don’t produce urine, different red blood cells, all of which I will discuss later.  All of these various oddities work together to allow one thing….flight.  It seems like the vast majority of adaptations that the successful dinosaurs made revolve around the ability to fly.  Feathers are lighter than hair, and insulate better.  Bone marrow is heavy, and provides little structural integrity.  Teeth are heavy, and carrying around a bag of urine inside your body definitely crimps your ability to soar.  Red blood cells that have nuclei (the difference between bird and mammal blood cells) are more efficient at carrying oxygen and are quicker to produces…making bird blood more able to support the high metabolic rate needed to stay aloft.  Getting the sugar shakes at 250 feet up is not an evolutionary advantage.

Chickens are omnivorous, able (and willing) to eat almost anything.  They have a very short digestive tract (again, lighter), that is very efficient at extracting nutrients from whatever they put in their beaks.

Birds have lung adaptations, great eyesight, and lay eggs…..all of which make flight possible.  (I am saying these like they are facts, but in reality, they might be adaptations that just followed along from their dinosaur heritage, and weren’t lost…..dinosaurs laid eggs and didn’t fly…..but it makes a good story, and is plausible).

Anyways….I will be developing the truly informative stuff over the next little while.  I hope it is useful to you, and gives you a different way to look at and evaluate the way your hens interact with the world.

Mike the Chicken Vet

Bird Health Awareness Week

Anyone who has followed this blog at all knows that my two main professional  passions are poultry health and welfare.  Since these two issues are so closely interdependent, anything that improves one will often improve the other.  In this vein, I am forwarding some information that I came across from our friends to the south.

Most agricultural organizations, including all the ones I work with, are very aware of the relationship between small, backyard flocks and professional farms in the area.  The farmers spend a lot of time, effort and money maintaining biosecurity to keep their flocks healthy, but the fact remains that any diseases circulating in backyard flocks is a threat to the people who make their living by caring for hens.  For this reason, most of the poultry groups are willing to extend expertise and advice to the people who keep hens as a hobby.   I hope the following information helps anyone with an interest in poultry, whether their flock is small or large.

The Maryland Department of Agriculture issued the following news release:

Bird Health Awareness Week is Feb. 24 through March 2, and the Maryland Department of Agriculture (MDA) Animal Health Section urges owners ofbackyard poultry flocks – or those thinking of starting one – to make sure they follow our six steps for keeping poultry healthy.

“Poultry is one of Maryland’s most important agricultural commodities, and we want to keep them all healthy, whether they are commercial, or fair and show, orbackyard flocks,” said State Veterinarian Guy Hohenhaus. “Bird Health Awareness Week is a good time to remind everyone of the important but easy steps they can take to have the most positive and successful experience raising poultry. It is also a good time to remind people that they must register their flocks with MDA so that we can contact them and help them if a disease outbreak were to occur. “

The following are MDA’s Six Steps to a Healthy Flock.

Step 1. Select Healthy Birds. MDA urges citizens to purchasechickens only from hatcheries that are certified by the USDA’s National Poultry Improvement Plan (NPIP) and hold a permit from MDA. NPIP hatcheries follow strict biosecurity practices, maintain detailed records of where their chicks come from, and have had their sites and chickens tested for particularly debilitating diseases. Anyone who sells or distributes hatchingeggs, live poultry and anyone who operates a hatchery in Maryland must meet NPIP standards and hold a permit from MDA. Residents are warned not to buy chicks that are sold online and delivered through the mail by uncertified and unapproved hatcheries. The practice is not only illegal but can be deadly to your flock. Find an NPIP hatchery. (www.aphis.usda.gov»)

Step 2. Register your flock with MDA.Backyard flock owners, who generally keep birds as pets or for private use of theireggs, are required, by law, to register their location with MDA. In the event of a disease outbreak, MDA will immediately contact all flock owners who might be infected and provide them with information and instructions about the specific precautions they need to take to keep their birds and families healthy. Flock owners not on the registry may never know a disease is rampant until their flock dies. Flock owners who are not registered put their neighbors’ flocks – and maybe even the state’s poultry industry – at risk. The Maryland General Assembly created the mandatory poultry registration program in response to the 2004 avian influenza outbreak on Delmarva. There are currently 3,948 flocks registered in Maryland. The registry is confidential, free and easy. For more information and to register (mda.maryland.gov») .

Step 3. Clean hands, boots, clothes, equipment, and housing to prevent disease. Raising flocks ofchickens, like raising any other pet, requires a certain amount of effort and vigilance if the animals and their owners are to stay healthy. Flock owners need to follow basic bio-security measures from the beginning to ensure their birds and families stay healthy. For more information about biosecurity measures. (www.aphis.usda.gov»)

Step 4. Quarantine any new or sick birds. Healthy flocks can be ravaged, even lost entirely, by one sick chick. Keep new chicks quarantined for at least 21 days until you’re sure they’re healthy. Veterinarians who treat pets do not usually treat poultry or livestock, but there are avian vets in Maryland who can be contacted if your flock is sick. To find an avian veterinarian, go to the Association of Avian Veterinarians website. (www.aav.org»)

Step 5. Test poultry before exhibition. All animals, not just poultry, that are shown at exhibitions must meet animal health requirements. Some requirements are different for in-state and out-of-state animals. Poultry, for instance, must be tested for PullorumTyphoid prior to an exhibit. For more info on exhibition requirements. (mda.maryland.gov») [1].pdf)

Step 6. Report sick birds to MDA Animal Health. Despite the best efforts of some flock owners,chickens sometimes do get sick and die unexpectedly. MDA urges flock owners to report sick birds to the agency if more than one bird in a flock is ill since that could be the start of a devastating outbreak. Call MDA Animal Health Program at 410-841-5810 to report an unusual disease in a flock. Unusual symptoms that may indicate your chicken is sick and should be reported include:

– Sneezing, gasping for air, coughing and nasal discharge

– Watery and green discharge

– Lack of energy and poor appetite

– Drop in egg production, soft or thin shells, misshapen eggs

– Swelling around the eyes, neck and head

– Purple discoloration of wattles, combs and legs

– Tremors, drooping wings, circling, twisting of the head and neck or lack of movement.

Want to learn more?

– Visit the MDA website (mda.maryland.gov»)

– Visit the USDA’s Animal Health website for more information: (www.aphis.usda.gov»)

– Participate in USDA’s Animal Plant Health and Inspection Service’s free webinar, “Growing Chicks Into HealthyChickens: Getting Ready for Spring,” on Thursday, Feb. 28 at 2 p.m. Register here. (www.aphis.usda.gov»)

– For regular tips on how to keep your birds safe and healthy, follow the APHIS’ Biosecurity for Birds campaign on Twitter @Healthy_Harry

Mike the Chicken Vet

Chicken Cinema

Hi Everyone;

I apologize for the lack of attention I have been giving to my blog lately….things have been busy, but that’s no excuse.  I have been very active with chickens, however, and today was no exception.  I got the opportunity to spend the morning with Norm Saito at the Ancaster Fall Fair (http://www.ancasteragriculturalsociety.ca/Pages/Fair/fairframe.htm) .  Many thanks to the fair organizers for all their help and accommodation.  Also thanks to the Egg Farmers of Ontario for putting me in contact with Norm in the first place.  I am impressed with the community outreach that the EFO is doing, trying to let people in the province know about poultry of all types.  They have the idea that letting urbanites know more about poultry can do nothing but improve the relationships the farmers have with the public, and I couldn’t agree more.

Norm Saito….the depth of knowledge this man has on various breeds and standards for fancy chickens was staggering.

Norm has been a judge of fancy chickens for over 40 years throughout North America.  He is the end-all and be-all of knowledge regarding Buff Orpingtons, Barred Rocks, Polish, Wyandottes, Minorcas, and Rhode Island Reds.  He also judges turkeys, peafowl, guinea fowl, ducks, and rabbits.  His background information on where each bird origionated….both geographically and through history (how bantam chickens were bred to be smaller versions of regular hens, and how many of the sport breeds are descendants of fighting cocks, once fighting became socially unacceptable) was amazing. 

We had a great time “talking turkey” for most of the morning.  He started his career with fancy chickens when his son was in Cubs, and wanted to get his “pet keeping” badge.  Norm and his son decided they wanted a chicken, so they purchased Sylvester, who lived in their basement until they moved.  The family loved the bird by then, and couldn’t leave him behind, so Sylvester came along, and became the base for a flock of fancy chickens that eventually numbered in the hundreds.

The creative process…it is WAY more complicated than I ever thought!

For anyone not familiar with video production, it is a LOT more complicated than I ever thought.  Worrying about background noises, direction of sunshine, background composition, etc. is really involved.  Plus, once I knew what I wanted to say, getting the phrasing right, and saying it in a way that sounded somewhat coherent was tougher than you’d believe.  I will be posting the interview video in a little while, once it is edited, and hopefully you will have no idea how many mistakes went into each of the little segments.

Hopefully there will be some information and insights that are of interest to people who raise and show these “beauty queen” chickens.  I don’t know how many of you have had the chance to see behind the scenes  to see how a fair poultry show is judged, but I sure am glad I got a chance to see it!

Winner in the Polish class….one of the stars of the video

  Mike the Chicken Vet

Bones, Shells and Hen Health

People keep backyard hens for any number of reasons…..for companionship, for comic relief, to fertilize the garden, eat bugs, teach kids about the circle of life or to eat table scraps.  But the main reason that most people have hens around is because they do all these things AND produce eggs.  Eggs are the lynch-pin that makes henning so popular.  You (and your kids) can see how the food the hen eats today becomes your breakfast tomorrow.  It is fascinating and awe inspiring….old broccoli into an omelette…..talk a bout a silk purse from a sows ear!

There is an aspect to egg production that puts the health of your hens at risk, however.  Each egg is presented to you in its own handy carrying case….the shell.  An egg-shell is made up of calcium carbonate.  It contains the entire

Hens in lay have “trabecular bone” that allows for the rapid storage and release of calcium when the hen is in lay. If the trabecular bone is depleted, the cortical bone (part that gives strength) will start to be used, resulting in weakness and pain for the hen.

amount of calcium the chicken can carry in her bloodstream.  This means that if a hen doesn’t eat any calcium, she will deplete her calcium stores very, very quickly.

A chicken’s bones are made of calcium phosphate.  In the currency of egg production, consider this the “bank”.  Hens eat feed that contains calcium….it’s her “income”….she deposits egg-shell….this is her “expenses”.  The bones act as a storage site (important, since she eats during the day, and deposits egg shell overnight).  Simple, right?

Sorta.   Getting enough calcium into a hen every day is tricky….the ration needs to be balanced for both calcium and phosphorus, and hens do NOT like eating a ration that contains more than 4% calcium (the amount needed if a hen is to lay an egg each day)…..it is very salty, and hens will back off feed when the calcium level is high in the diet, until they get used to it.  Giving oyster shell as a free-choice supplement is not enough if you have a modern laying hen breed.  Hens eat oyster shells, and they stay in the gizzard as the acid there dissolves them

The black stuff inside the gizzard is limestone…another source of calcium. It stays in the gizzard until it shrinks to less than 3mm in size, then it goes through the gut. This gizzard is quite full, but the large particles won’t provide enough calcium for the hen, if they are the sole source.

slowly….thus it is a constant drip of calcium for the hen.  Helpful, but if it is the only source of calcium, the physical limits of the gizzard, and the slow release of the calcium means the hen won’t get enough.

To further complicate things, the bones are made of calcium phosphate….therefore phosphorus is also very important for bone health (and indirectly, shell quality).  The problem is, the phosphorus level needs to be in the proper ratio with the calcium…..too much phosphorus is dangerous to the hen, and she must get rid of it through her kidneys, and will (strangely) result in the same condition as insufficient phosphorus.  In a backyard, feeding minerals becomes more art than science.  Feed sunflower seeds, edamame, flax seeds and oat bran (foods high in phosphorus), but not TOO much…..and there is no target amount to feed…..it depends on the amount of calcium the hens consume…..the ratio of calcium to phosphorus is the important number.

To further complicate things, if you have a modern type laying hen, her physiology is set to lay an egg a day (pretty much).  She will do this, regardless of the state of her bones, or the balance of her calcium intake vs output.  The result is poorly shelled eggs, weak bones, egg bound hens or chickens that are too weak to survive well.  Heritage breeds are not as physiologically driven to lay eggs, and will just stop laying if the mineral balance is poor.

The answer is to feed hens a ration that is balanced with a lot of calcium in it, and appropriate amounts of phosphorus added.  Feed treats and scratch as just that….treats and amusement.  Don’t try to balance your hens rations piecemeal….it is all but impossible, and the hens will suffer.  Another way to approach the problem is to use heritage breeds, which will go out of lay  much more easily, and spare themselves the effects of calcium depletion.  You will get fewer eggs, but also less problems.

Mike the Chicken Vet

What Eggs are Safest?

I work in the professional egg world.  I know by name the vast majority of people who supervise the production, transport, grading, marketing and delivery of the eggs you find in your grocery stores, restaurants, farmers markets (yes, legally, those eggs need to be professionally graded too), and industrial users of eggs (think bread, cake, cookie, cereal, etc. makers).  I know how much care, concern, time, money and worry is dedicated to preserving the safety of eggs.  Being a vet, I am very involved in advising on many aspects of egg safety, right from chicken health to giving opinions on egg handling, and even national programs for salmonella control.

We, in the world of Canadian large-scale egg production, are quite proud of our safety record, and the programs we have in place.  We often debate whether small producers (read backyarders and hobby farmers) can produce a product that is comparable in safety.  We snicker a little at activists that say we need to get away from large-scale farming, since you can produce healthier eggs in your backyard, or on your apartment house roof.  How on earth can removing the expertise and care that we provide result in a healthier product?  By concentrating the number of birds on a farm, you allow a person to focus strictly on the care and protection of the hens….learn about them and become truly an expert.  I admit to having this opinion much of the time.

Many, many people disagree though.  “Factory farms”, “industrial production”, “bacterial breeding grounds” have been used to describe professional farms….unfairly, I think, but the terms are sincerely used by many people.  The problem is that there are many confounding factors.  Depending on what you WANT to read in a paper, almost any study can say anything.  Professional, caged farms are much bigger than extensive farms, and exponentially bigger than recreational farms.  If there is 1 contaminated egg per 1000 in a cage barn, the farm will produce many contaminated eggs per day.  A backyard flock with a rate of 1 contaminated egg per hundred would only have 1 contaminated egg per month.  If you eat 2 eggs per day, however, which is safer? 

The fact remains (check any activist website for examples) that many studies show that large farms have higher bacterial contamination.   Conversely (check any egg farming website for examples) many studies show that professional farms are much safer, contamination wise.  So, what’s right?

There is a very recent scientific paper from Spain that describes bacterial contamination that I think is quite balanced.  It must be taken with a grain of salt, however, since in North America, all graded eggs are washed, whereas in the EU, this is not the case.  Also, the rules on antibiotic use is different.   That being said, the study found that there was more significantly more bacterial contamination in free-range, organic and backyard (called “domestic eggs”) production than in free run (birds free inside of a barn), while cage barns had the least contamination.

Having said that, the authors went on to evaluate the antibiotic resistance in the different systems.  Free run barns were worst, then cage barns, then free range (outside), organic and backyard flocks had the least antibiotic resistance.  Both these findings make sense to me.  Large scale farms have a higher tendency to use antibiotics (thus the resistance), whereas backyard flocks almost never medicate (sometimes that is itself a problem). 

Which is more important?  I don’t know.  Antibiotic resistance doesn’t necessarily mean that the bacteria is likely to make you sick…it just means that if you treat an infection, you are more likely to clear it.  Some resistant bacteria don’t make you sick at all….some susceptible bacteria make you deathly ill, very quickly.  On the other hand, if you DO get sick from a resistant bacteria, it can be a serious problem. 

Bottom line, eggs from backyard flocks are more likely to be contaminated by bacteria than anything you would buy in a grocery store.  Be careful with them….wash your hands; keep the eggs in the fridge, separate from other foods; rinse eggs in running water to remove contamination before packing them in the fridge……and then relax.  Contamination rates are very low, and most bacteria are not pathogenic.  Take reasonable precautions and then just enjoy the fruits of your labours.  You are as likely to give yourself an ulcer from stressing about the bacteria as you are of getting food poisoning.

Mike the Chicken Vet

Eggless Chicken Born?!?!

Saw this story forwarded from the Daily Mirror in Sri Lanka…it is amazing!!

The Miracle Chick

In a zoological anomaly, a hen in Sri Lanka has given birth to a chick without an egg.

Instead of passing out of the hen’s body and being incubated outside, the egg was incubated in the hen for 21 days and then hatched inside the hen. The chick is fully formed and healthy, although the mother has died.

PR Yapa, the chief veterinary officer of Welimada, where it took place, said he had never seen anything like it before. When examining the hen’s carcass he found that the fertilised egg had developed within the hen’s reproductive system, but stayed inside the hen’s body until it hatched.

A post-mortem of the hen concluded that it died of internal wounds.

I have seen a lot of funky looking eggs, but have never even heard of a chick being born outside of an egg.  Eggs come in a variety of sizes, shapes and colours naturally. 

Quite a range of normal colours and sizes.

Once you work in the abnormal eggs, the range is extensive.   I was in a barn today where many of the brown eggs had “targets” on them….perfectly round white rings around a dark circle on the side of the egg.  I didn’t have a camera with me though….figures.

I’ve seen double-yolked eggs, triple-yolked eggs, shell-less eggs, round eggs, double-shelled eggs, and yolk-less eggs. 

Hen Reproductive tract

The double- and triple-yolked eggs are simply the avian version of twins and triplets, and are not that remarkable.  Double shelled eggs are odd (and rare), since the egg has to form in the shell gland, then be moved back up the reproductive tract to the magnum, where new membranes are added, then new shell is deposited as the egg re-descends through the shell gland.

These abnormal eggs are interesting, but should cause no concern to a flock owner.  There are eggs that are

Soft shelled, wrinkled and shiny eggs

symptoms of problems, and recognizing them will help you diagnose problems with your flock early enough to treat them effectively.  Soft shelled eggs and slab-sided eggs are symptoms of calcium deficiency in a hen.  Pimpled eggs can also be a sign of low calcium, if the shell is thin (pimpled eggs can be of 2

Slab Sided egg

types…1) the shell is normal thickness, with extra calcium causing raised nodules on the surface, or 2) thin shells with small areas of normal-thickness shells, that then seem to be raised areas).

 Slab sided eggs occur when an egg is held inside the bird for a day, and the next day’s egg comes down the tract, and lies against the formed egg that is in the way.  The new egg is a soft-shelled egg and deformable….it sits against the old egg as the shell is deposited on it….thus the flat side on the egg, and the round area of wrinkles around the flat side.  If you see these types of eggs in your nests, you should immediately assess the amount of calcium, phosphorus and vitamin D that is available to the hens, since hypocalcemia can result in weakness, sickness and death in a hen.

Another egg that should alert you to possible problems is a wrinkled egg.  It is usually a sign of an infection of some type.  Viral infections such as infectious bronchitis, egg drop syndrome and avian influenza can cause these types of eggs, but so can other illnesses that cause the hen to be fevered and dehydrated.  Imagine a yolk that gets covered by membranes in the magnum, but does not get its share of protein and water added to it while travelling through the

I've seen this only twice, but it does happen.

infundibulum….a partly full bag of water will result.  Once the calcium is added, the egg will stay wrinkled until it is laid.  A wrinkled egg is almost always a sign of illness.  Check that your hen is not wounded (wound infections can cause wrinkled eggs too), or showing any signs of illness.  Look carefully, because hens are often very stoic. 

It is, of course, important to know what is normal for your breed and type of hen.  Some hens lay dark eggs consistently, and light eggs may be a sign of problems….however some hens lay light brown eggs all the time.  A change is usually worth looking into….often subtle changes in egg color or texture can be the earliest sign you will get that your hens are missing something in their diet, or are facing a health problem.

If you find this egg in your coop....look for an escaped emu in the area!

 Mike the Chicken Vet

Chicken Vision

You should be able to file this entry into the “stuff I didn’t know” category.  I have had some experience with chicken vision, and was aware of some of the basic ideas of the “weirdness” that bird sight entails.  As I started writing this, I wanted to make sure I got my facts right (ish), so looked up a few things, and they led to a few more, and half my evening got lost in obscure eye facts that will never be clinically useful to me, but will be GREAT fodder at the next cocktail party.

How do chickens see?  What do chickens see?  Why do they bob their heads around like that?  Why do they look at you sideways?  Can they see at night?  How much can blind chickens see? 

Chickens see the same way we do….light comes in through the cornea and iris,

Chicken eye....about 25 times as large as a human eye...as a percentage of head size

then stimulates nerve endings in the retina at the back of the eyeball.  A major difference, however is that chickens have tetra-chromatic vision, while we have tri-chromatic.  In english, chickens have 4 wavelengths they are sensitive to, while we see 3 (red, green and blue).  The chicken eye sees red, green and blue as well, but they are also sensitive to ultraviolet light.  This seems kinda interesting at first glance, but the implications are actually staggering.

The fact that chickens see an extra sector of the light spectrum means that EVERYTHING they see looks different from what we see.  Their concept of the

The 4 peaks of sensitivities of the chicken eye.....they see UV light (grey line), as well as all the colours we see

green colour of grass is as different as our comparison of aquamarine and the colour of grass.  We have no concept or description for how much UV is reflected from any substance.  There is evidence that birds can find direction by looking at the sky and seeing the gradation of UV, and knowing which way is north as easily as you or I looking at a grey-scale drawing and knowing which side is closer to white.  It also means that we have a really hard time understanding what they are seeing.  In the following picture, there is a cockatiel.  Males and female cockatiels look the same to us, but if you

Left: bird and egg the way RGB eyes see them….Center: UV reflection of the same bird and egg….Right: What a chicken sees….

 look at the UV contribution, you see something else.  The picture on the left is human sight…..the picture in the middle is UV spectrum only, and the right hand picture is a rendering that approximates how another bird would sense that bird. 

 

Now….chickens have a disability when compared to us….their night vision is poor. This is a big part of the reason that chickens need protection at night from predators.  The retina in mammals is made up of rods and cones…..rods to see at night, and cones to see color.  Chickens have very few cones, and they are not especially sensitive.  This difference between rod to cone ratio, and the light sensitivities of cones in birds vs mammals is explained because mammals all but disappeared from evolution long ago, and the only types of mammals that survived  were nocturnal and insect eaters.  Mammals that survived this evolutionary bottleneck re-developed colour vision after millions of years, but since we evolved our cones from a different starting point than birds (they evolved from dinosaurs, and never spent millennia as nocturnal creatures), we developed our colour vision a little differently.  It’s another case of convergent evolution….kinda like whales and dolphins evolving to look like fish, because that’s the body type that works best in the water.

Bird’s colour vision is also different from ours because they have coloured filters mixed in with their nerve cells……little coloured drops of oil filter out different wavelengths, and act similarly to wearing yellow goggles when skiing

This is what you look like to a chicken....or at least a good guess

on a bright day….the contrast is enhanced.  Now imagine wearing yellow and blue and red goggles all at the same time…..it increases contrast and brightness and sensitivity, all at once, and we mammals can’t even imagine what it might look like. 

Chickens also have much better motion sensing ability than we do.  Not as good as hawks, but better than us….again because of a structure called a double cone in the retina.  This is important if you use flourescent lights in your coop.  Flourescent lights flicker on and off at a rate above what we can see….you notice it on old flourescent tubes that are dying….the flicker rate slows down and we can see it.  It is exceptionally annoying.  Birds can see the flicker in many flourescent lights, especially dimmable ones that are at lower intensity.  It would be like being in a dance club with strobe lights on…..all the time….it drives them nuts…literally.  On objects sitting still, chickens may not have as much acuity as we do, however.  This explains why hens are as “spooky” as they are when somebody makes a sudden movement, and why one bird jumping from something can cause the entire flock to take wing, even if they didn’t see the offending stimulus. 

Birds and mammals have a structure called a fovea in their retinas too…..its a small pit that, because of its shape, acts as an image enlarger.  You can see yours in action by looking at something out of the corner of your eye, then looking at it directly in front of you…..its way clearer in front of you, and why you look slightly down at anything you are concentrating on (the fovea is a little above the middle of the retina).  Chickens have 2 foveas (fovei?), and they act a little differently.  One is for distant vision, and one is for in close….think of built-in bifocals.  The funny thing is that the up close one is oval, and sideways….thats why, when you approach a bird, once you get to the focal distance of about 2-4 feet, birds will often bob their heads, and tilt their heads somewhat sideways to get the image better lined up on the second fovea.  Birds actually can’t reliably recognize flock mates until they are within about 24 inches.

Finally, blind birds can see light.  Birds reproductive cycles are controlled by their pineal gland, which is located in the middle of the bird’s forehead, just under the skull.  The skull is thin enough that reasonably bright light penetrates it and will still stimulate the hormone cascade that begins lay.  Even blind chickens can “see” spring coming.

This post is way too long already, so I will cut it off here….just remember, even if you and your chickens can see eye-to-eye, you still won’t see what they see…..keep it in mind when you try to figure out why they do what they do.

Mike the Chicken Vet