Monthly Archives: February 2012

Where’d they come from?

Chickens are a weird study in domestication.  People have had chickens around for a REALLY long time….but nobody is really sure where they came from exactly…

Red jungle fowl, and his great, great, great, great....(you get the idea)....grandson

It seems that red jungle fowl were hybridized with grey jungle fowl about 8000 years ago.  The original strains are likely to have come from Thailand, but domestication seems to have happened independently several times in southeast Asia and China between 5400 and 5200 BC.  I can’t help but imagine a Chinese Johnny Appleseed-type guy….wandering from village to village saying “if you keep some of these birds in your house, you won’t have to go hunting all the time….”

Cishan Site...a 10,000 year old site where 6000 year old chicken fossils were found, indicating this may be one of the earliest sites of chicken domestication

A couple thousand years later, the chicken made it to the Indus valley (around 2000 BC), which has been called the cradle of agriculture.  It was this are where many of our domesticated animals were domesticated, as well as many of the hybrid grain and vegetable crops that are the progenitors of todays farming across the world.  It is from the Indus valley that chickens found their way to Europe and Africa.

Now that we know where chickens came from, how have they changed?  It’s been a LOOONNNGGG time, and we’ve been messing with these birds pretty aggressively.  People have been VERY successful in increasing the ability of the bird to produce eggs.  Jungle fowl will lay around 5-6 small eggs per year.  Leghorn (the strain of white hens that are the most commercially successful chicken throughout the first world) hens will lay over 325 eggs in a year, and the eggs are much larger than the wild counterparts.  That is pretty obvious, and expected.


Laying hens split from jungle fowl lineages about 6000BC, and split from broiler chickens and Rhode Island Reds about 100 years ago


What is interesting is that domesticated animals (all of em…not just chickens) gain some traits when being domesticated…..think about it.  Domestic dogs, cats, cows, chickens, pigs…..all of them become less fearful of predators, have a less serious fear response, and show less interest in novel stimuli.  All that is understandable as animals are chosen on their ability to cope in a confined, human-centric environment….but there are other things too.  The one that amazes me is that domesticated animals uniformly turn more white.  I don’t know why….it makes sense that domesticated animals don’t need to be as camouflaged, but why bother changing?…..also…does that mean that blondes are more evolved than the rest of us?

 Domesticated chickens also use a more energy-conserving foraging strategy and are less active in fear tests, compared to jungle fowl.  This means that, given a choice, they PREFER more bland food, as long as it is easier to get, where as jungle fowl will work harder to get tastier tidbits.

The more predictable environments that leghorns find themselves in have caused them to be more risk averse, and less responsive to things like food deprivation.  Leghorns will act much more normally during experimental food deprivation than jungle fowl, who will spend more time searching for food, and spend more time off perches (a risky behaviour for hens in a jungle).

Maybe even more intriguingly, there are several traits that have not changed much from junglefowl….hens still flock together much the same way…the same inter-bird spaces, the same synchronization of behaviour, similar responses to predators.  Both leghorns and jungle fowl imprint readily on objects as babies, and will approach that object readily later in life….but leghorns have less flexibility in this….in one experiment, they could not get used to a blue ball in the pen, where jungle fowl imprinted on it readily.  Leghorn hens also show more fear of a novel environment than jungle fowl.  Leghorns will adventure less, and show more agitation in unfamiliar surroundings.

Other behaviour remain important to the hen, while being unnecessary in captivity.  Nest building is an important activity that hens will work hard to fulfill, as is foraging for food (interesting that leghorns will choose to eat bland, easy to get food in preference to novel foods, yet will then spent time scratching for food after they have eaten their fill), perching and dustbathing. 

The fact that jungle fowl are still alive and available for study is a rather unique situation.  Other domesticated farm animals do not have an ancestor to be compared to.  The aurochs (cow ancestor), mouflon (sheep ancestor), and tarpan (horse ancestor) are extinct, and the wild boar that exists today is very different from the ancestor of the modern pig.  As such, these species’ behaviour are not compared to the ancestral in order to try to guess what they would prefer.  I think it is dangerous to look at jungle fowl and expect that laying hens will desire or prefer the same things.  There is information to be gained from studying jungle fowl, but laying hens cannot be un-domesticated, and should be evaluated on their own when deciding on how to manage them, and what behavioural needs must be accounted for.

Mike the Chicken Vet

Whats in an Egg?

It’s something you don’t think about all that often.  You go to the fridge, grab what you need, crack ’em and try not to get any shell into the slimy, sticky goop that comes out. 

The parts of an egg. The Chalazae are twisted because the egg rotates inside the shell membranes as it progresses past the infundibulum....natures version of "cats cradle"

Most people never really consider what is in the bowl or pan beyond that.  That’s sad….because the egg is really an amazing piece of engineering.  It only takes 22 hours to produce, it is impressive nutritionally, it is a source of both vaccines and medicine, AND it comes with a handy carrying case!

With today’s highly efficient strains of laying hens, an egg per day is not far from the truth.  This means that each day, the hen takes the most dominant follicle, wraps it in pure, digestible protein, water and membranes, then protects it inside a shell, and delivers it into the world.

The hens reproductive tract, with the parts labelled. The ovary makes ova (yolks), which then are covered during the 22 hourr trip down the reproductive tract

The ovary makes ova (yolks), which then are covered during the 22 hour trip down the reproductive tractThe infundibulum actually “plucks” the yolk off the ovary, and holds it for about 15 minutes. It’s here that fertilization will occur, if it is going to.  Then the 13 inch long magnum adds the thick albumin over about 3 hours.  In the isthmus, membranes are added which act as the scaffolding for the shell to grow from.  This takes about 75 minutes.Water is also added to the egg once the membranes are in place, in order to “plump” out the egg, and make it, well….egg shaped.  Then the egg sits in the shell gland for about 18 hours before being laid very quickly…usually just after daybreak. The addition of water is important, or you can end up with wrinkled eggs….the shell just covers the membranes, which are thin and pliable….without being plumped out, you get this :

I use this as a sign of stress in a laying flock.

You can get this type of thing from some diseases that injure the uterus, or if there is something that makes the egg leave the isthmus area too quickly.  During this relatively short period, an amazing package has been developed.  As someone who a) has kids and b) is in training, and wants to lose some weight as well as build muscle, I am acutely aware of the low calories and high protein available in the egg.  Eggs are still considered the yardstick against which other proteins are measured against, with beef getting a rating of .93, and whey protein has .25 of the quality of protein in an egg.  I also find it easier to get a scrambled egg into the kids than almost any other “healthy” food…(there is some debate in the house as to whether macaroni and cheese ranks as “healthy” food or not….).  For the low cost of 70 calories, eggs contain 6g of protein and 5g of fat.  They have an alphabet soup of vitamins, and iron, selenium and choline.

See....Lots of good stuff, and only 70 calories

See….Lots of good stuff, and only 70 caloriesThis is the breakdown of a “normal” egg.  If you feed chickens special things, such as lutein, Omega 3 fats, extra vitamins and potentially other things, you can harvest them from eggs, which make them the leading edge of the science of neutraceutical development.  Preventing macular degeneration, improving brain development and providing extra nutrition to people who don’t consume much food (think ill people, or the elderly) are all functions of eggs right now…the future has lots of potential.The other thing that is a nice characteristic of eggs is the versatility they have for preparation.  Hard boiled, over easy, quiches, scrambled, poached….all are quite different from each other, and eggs pick up the flavour of whatever you cook ’em in.  All in all, not a bad piece of food technology.  There are times, however, when you feel an urge to be a “purist”, and get back to nature….there is only one way to appreciate ALL the characteristics of eggs….not for the squeamish, however… 

Hard-Core Egg Consumption.....not sure what the health department would say...

Mike the Chicken Vet

Zoonotic Diseases and Chickens

Have you ever noticed that kids never get sick at the same time?   My youngest is laying like a puddle of water on the couch, recovering from the “gift” my daughter gave him.  We did tell her it is good to share…..

It got me thinking about some of the risks of people getting sick when they get into backyard chickens.  Like most things, the impressions people get from the media are skewed.  The big media scare around chickens is naturally bird flu.  Contagion, Outbreak, and a whole bunch of made-for-TV movies make it seem like we are poised on the brink of a world-wide viral catastrophe.  What makes the stories so engaging is that they are plausible….it truly could happen.  Of course, asteroids could collide with earth,  the magnetic poles could reverse, or a rabid dog could terrorize a small Maine town. 

Bird flu is a concern, but it is a risk that is minimal in North America.  We have never had a bird-human transmissible flu virus on the continent.  If we ever get “bird flu” in Canada, I will bet my next paycheck that it arrives on an airplane, carried by an infected person….likely from a country that is already dealing with a human outbreak.

There are risks with having backyard chickens, however.  Having birds in your backyard means having poop in your backyard, and in your coop.  Having poop in your backyard and coop means you have bacteria in your backyard and coop.  Bacteria will occasionally will make you sick, if you get it in your body.  Salmonella, E.coli, and Clostridium are all types of bacteria that can live in chickens that are a threat to human health.

The nice thing about eggs is that there is only really one bacteria that will contaminate the interior of an egg before it is laid.  Salmonella enteritidis can live in the ovary of the hen, and be incorporated in the egg.  The unfortunate thing is that S.e. doesn’t necessarily make the hen very ill….so you could possibly eat an egg from a contaminated hen without knowing it.  The amount of money and time spent controlling this bacteria by professional farmers is staggering.  We have programs of regular testing, and plans for what to do if the bacteria is ever found….even if we just find it in the environment, and NOT in any eggs.  This makes our commercially available, graded eggs very safe.  In your backyard, it is much more difficult to be sure….  It is expensive and technically difficult to isolate S.e. from a contaminated hen….let alone one who might, or might not have it.  The thing to keep in mind is if anyone in your household, or anyone who eats eggs from your hens, gets sick with diarrhea (especially bloody) or a high fever, PLEASE let your doctor know that you have hens, and eat ungraded eggs…..catching an infection like this early is very important.

The main difference between having chickens and having a dog is that you are planning on eating stuff that comes out of your chicken.  This means that the bacteria in your yard could easily be carried to your kitchen.  Also, bacteria in your yard can get on hands and clothing easily….also adding risk for illness.

As I said above, the only real risk for contaminating the inside of the egg is Salmonella, but eggs come out of the hen moist and warm (>40 C).  That means that if the egg lands in a contaminated spot, it can “suck” bacteria (especially E.coli) through pores in the shell, as it cools.  It is crucial to keep the nest boxes clean, and be very careful with any egg that is not laid in the nest box.  Also, the shell is a very good barrier to infection, but if the egg is cracked, contamination is a much bigger risk.  Once a few bacteria get in through the shell’s defences, it is an ideal spot for the bacteria to thrive, and the number of bacteria will grow exponentially if the conditions are right.

Here is a bit of a checklist to decrease human health risks for urban farmers:

  1. Wash your hands EVERY time you interact with your chickens
  2. Have shoes dedicated to chores time.  Leave them at the back door, and don’t walk through the house with them.
  3. Collect your eggs as soon as practical after they are laid….get your eggs in the morning if possible, ideally before they cool off completely.
  4. Be cautious with how you use eggs any time you have any signs of illness in your flock.
  5. Be careful with any eggs with obvious manure contamination, or have cracks…..look into proper handling of these eggs, or throw them out.
  6. Rinse your eggs in cool, running water after you pick them, then clean your sink with a disinfectant (ie bleach).
  7. Keep your eggs in the refrigerator to keep any bacteria in the egg from reproducing.
  8. Always cook your eggs well to help kill any bacteria that might be present.
  9. Don’t keep your chickens in the house, unless they are in a separate area, with a separate airspace….it is intimate contact with live birds that is a risk factor for influenza transmission from birds to people…..remember, in this situation, you are more likely to make your hens sick, than they are to infect you.

All these steps are simple, straight forward and free, but if you don’t respect the fact that you are producing food, and take the necessary care, the consequences can be significant.

Mike the Chicken Vet

It’s Food Freedom Day in Canada

Whew!  Just in time….I, like you, have just made enough money to pay for all the food I will eat this year….assuming you are as average as I am.   I’m not 100% sure how it works for the kids….they don’t have jobs, and they still eat quite a bit, so….they may have to go on a diet.  But, bottom line, we pay less than 10% of our GDP on food each year.  According to the government, each household spent $7440 on food in 2008, which was 1.8% higher than 2007.  (Somehow, the government knows EXACTLY how much I owe them the day after my income tax is due, but can’t tell me how much we spent on food any more recent than 2008….) 

In the 1960’s, the amount we spent on food was around 18.7% of our income.  I find it amazing that we spend so little for food in a country that, lets face it, is relatively inhospitable to life in general for 7 months of the year.  Much of our food cost has extra charges for transportation, energy and housing….whether its greenhouses, or barns with heaters.  Imagine being an egg farmer in the tropics….put up a roof, and some netting, and your barn is built….here we have walls, insulation, heaters, big fans, and computerized controls so that our birds don’t freeze in the winter or cook in the summer.

Anyway…I was looking at the numbers for food freedom day, and noticed a few other official numbers that were pretty interesting.  These numbers are from 2009, but are not too far off what is going on today.  The average person eats 16.1 dozen eggs per year (193 eggs), which is down from a high of 23 dozen (276 eggs) in 1960.  Of these 193 eggs, 70% are sold in the shell, and 30% are consumed as processed eggs.  Processed eggs are sold at retail, to hotels, restaurants and institutions, are sold to further processors for the manufacturing of many foods (bakery products, mayonnaise, noodles, etc.) and speciality items such as shampoo, pet foods and adhesives.  Consider Chinese consume 349 eggs per person, Mexicans consume 345 eggs per person, and the Japanese consume 323 eggs per person per year.

Canadians have a vast amount of choice when it comes to eggs.  Eggs farms in Canada produce white, brown, Omega-3, free-run, free-range, vitamin enriched, lutein enriched, and organic eggs.  They come in pee wee, small, medium, large, jumbo and double-yolk sizes.  There are a few farms now that are testing out aviary and furnished cage systems.  It is amazing to live in a country where we can afford to have this much choice!

So….now that I have enough money to buy all my food for the year, I have 3 days to save up for valentines day… I don’t have to spend extra money on a comfy couch.

Mike the Chicken Vet

Chicken Farming Across the World

My trip to Atlanta was, as always, an eye-opening trip.  One of the things that stuck with me, as I wondered the aisles, was the number of international exhibitors.  I got freebies for my kids that I can’t read.  (International exhibitors give away the BEST stuff….I got an oriental labelled magnetic chess set from one of them!….I’m not even sure what country the company was from.)  There were entire aisles where spanish and chinese were the main languages spoken.  It made me think of egg farming elsewhere in the world.  I talked to an Egyptian farmer, who had to make his own fans, because of some embargo that didn’t allow him to import equipment that he thought was decent quality.  Then a farmer from India who was concerned about air conditioning his chick barn so that they didn’t die from heat prostration (they like temperatures of 94F…..and he had to COOL them to that temperature!!).

Then, at one of the lectures I attended, there was a “Future of Chicken Farming” video shown from the United States that was made in 1946.  The description of the challenges and goals of the farmers of the time were amazing….there was no such thing as a broiler-type chicken then….people cooked up and ate laying hens when they were done laying.  The goal of the time was to try to develop a bird with a reasonable amount of meat on it….how things have changed.

Anyway, I started looking around for examples of different egg farming practices from around the world.  Many of the modern egg farmers across the world mostly deal in similar technology….the world is shrinking.  But the traditional and smaller farms vary considerably.  As do the attitudes towards egg handling and food safety.  I honestly don’t know if any of these pictures are representative of egg farming in any of the places or times represented.  I found them interesting, and eye opening.  You may find some things that you could apply to your backyard, or possibly gain an appreciation of the opportunities that we have that other areas do not share.

Employee of a 1940s egg farm, washing eggs for sale in the local store. My 5 year old would start a new product..."pre-scrambled eggs".


Proud farmers, displaying their best 1910.


Feeding Chickens in the 1950s.


Govornment Farm in Victoria, BC. Not sure of the year. Govornment efficiency....the great constant across the years.


An Egg Farm in Honduras


An egg farm currently for sale in the Phillipines....from the realtor ad.


Some hens in Australia


Interesting way to deliver birds to market in Phillipines.


A farmer in just never see saris in barns in Canada


Mozambique egg farm


I LOVE these egg cartons in China....don't believe they are widely used, but they should be!


Back in the 1950s, advertisements were simipler....and more accurate!


Egg market in Korea....not a fridge in sight.


Farm in Japan....much more intensive than here....


Chinese Egg Farm....again, very large scale

Mike the Chicken Vet.