Monthly Archives: October 2013

Welfare Impacts of Different Laying Hen Housing

Many people have read and commented on my previous post, where I tried to give some context to an animal activist video that attacked professional egg farmers in Canada. I have had numerous questions regarding housing types, and how “Welfare Friendly” they are. I am convinced that it would be easier to tell you how the colour purple smells. Anyways, here is a VERY BRIEF and superficial description of the welfare impacts of housing. These facts are based on scientific evaluations by some of the leading welfare scientists in the world. If you are “sciency”, I have included references at the bottom of the post, so I don’t get accused of making things up.

First, it is important to realize that animal welfare is generally evaluated under 3 sets of schemes.

1) Biological functioning measures an animal’s response to its environment. Mortality rates, production measures, corticosteroid levels, and any other measurable parameter will fall under this scheme. Welfare is assessed by the ability of the animal to adapt to its environment, and if it can adapt successfully, the welfare is felt to be good. For example, if you have a hen in a barn with a temperature of 15 degrees C, and her cortisol levels are normal, she is not ill, etc, etc, then you would say she is able to adapt to that environment, and her welfare is good. If she is in a 5 degree C barn, and her stress hormones are high, her body temperature is below normal, etc, you would say she cannot adapt to that temperature, and her welfare is poorer.

2) Affective state refers to the feelings of the animal. It is the feeling of hunger that is the problem, not the fact that the animal is hungry. Fear, frustration and boredom are important considerations in this approach, regardless of the physical state the animal is in. One caution with this approach is that affective states are extremely difficult to measure directly. Affective states can only be inferred from the actions the animal takes. For example, a shivering dog may be said to be cold, but she may actually be nervous, or excited.

3) Natural Living. The premise of this approach is that behavior evolves in a method similar to physical characteristics, and that extraneous behaviours will be phased out because they are too costly for the animal to maintain, if it is not important to the survival of the animal. Thus, any behavior, drive or urge that remains must be important to the animal, and for good welfare, the opportunity to perform all natural behaviours is necessary.

The welfare effects of different housing systems for laying hens are complicated and multi-layered. Conventional cages are heavily criticized because they severely restrict behavior and movement. They do provide many welfare advantages as well.

Typical modern conventional cage

Typical modern conventional cage

Cages provide excellent health and environmental benefits for the hen. They also effectively control group size, resulting in less inter-bird aggression and cannibalism. Health advantages provided by cages include less viral and bacterial infections, less parasite infestations, less bumblefoot, lower mortality and less antibiotic usage than loose housed or aviary flocks. Hens in cages also have less competition for feed and water. Environmental benefits delivered by cage systems include the lowest ammonia and respirable dust levels. On the downside, cages predispose hens to metabolic imbalances such as osteoporosis and fatty liver. Osteoporosis increases the risk of fractures during handling at depopulation. It is assumed that fear and boredom are inevitable consequences of barren environments, and natural living is very poorly provided.

Furnished cages are larger cages that contain perches, nest boxes and a scratch pad that has substrate on it to encourage

A Furnished Cage in Ontario

A Furnished Cage in Ontario

dust bathing. Mortality rates and bone strength are improved over conventional cages, and this housing system results in the least fractures overall. Infection rates, aggression and cannibalism are the same as conventional cages. Foot infections are more prevalent in furnished cages than conventional cages. Affective states in furnished cages are improved over conventional cages because of the variety of activities and social interactions that hens can perform, reducing boredom. Natural living aspects are improved due to the ability to perch, dustbathe and lay eggs in a nest, but is still very limited.

Loose housing systems (aka floor barns, or free-run barns) provide hens with a much expanded repertoire of behavioral

A free run barn in Ontario

A free run barn in Ontario

abilities, allowing hens to lay eggs in a nest, dustbathe, and forage. Hens are motivated to perform all of these behaviours, although to differing degrees. The barn in the picture has perches, although not all do. Aggression is higher in this housing system, and bone fracture incidence is around 60%. Ammonia and dust levels are high, with levels that are 3-4 times that of aviaries. Affective states are extremely variable, heavily dependent on the rank of the hen in the social hierarchy. The affective states are generally thought to be better overall than conventional cages. Natural living is improved over cages, due to the ability to nest and perch, but still limited.

Aviary housing is a system in which the hens are free in the barn and can access different levels throughout the barn. This system results in the best bone strength, but perversely the highest number of fractures, with up to 85% of the hens

An Aviary Barn in Ontario

An Aviary Barn in Ontario

getting a broken bone by the end of the lay cycle. Aviaries provide the widest repertoire of behavior, and the various heights allow submissive hens to escape effectively, and thus aggression is reduced from free-run barns. Ammonia and respirable dust are intermediate between cages and free-run, with levels 5-7 times that of cage barns. Affective states are assumed to be better than free-run barns, due to decrease in aggression and the thus fear, but are still dependent on social hierarchy. Natural living is improved over free-run due to the ability to fly, and perch in high sections of the barn.

Free range flocks have the ability to go outside. The range may be associated with a free-run barn, an aviary, or no permanent structure, only a mobile shelter to provide food, water and shelter. In Canada, free ranging can only occur during times of the year when the weather is reasonable. For several months of the year, the flocks are essentially free-run or aviary flocks, since going outside in the winter is not practical. Chickens in this type of housing have the ability to explore, experience weather and natural light and perform all their natural behaviors. These behavior benefits come at the cost of increased mortality, increased infections, predation and poor environmental control, resulting in thermal stress and discomfort from poor environmental condition such as mud and rain. Affective state is very good due to the ability to control her destiny, and make choices. Natural living proponents assess this housing system as far superior due to the range of natural behaviours it enables.

On top of all the considerations inherent in the physical layout of each housing system, the ability of the farmer to manage each barn can overcome many of the welfare differences between the systems. A well-managed cage barn will provide better welfare than a poorly managed aviary. The reverse is also true.

It is obvious that the three paradigms for evaluating animal welfare are often at odds with each other, and that each housing system satisfies each scheme to a greater or lesser extent. The housing system that provides the best welfare depends on the priority you place on each of the ways of measuring welfare. If natural living is the most important priority to you, cage systems will never be considered good providers of animal welfare. If you feel that it is preferable for the hens to be bored, rather than at greater risk for illness and dying, cages provide unparalleled welfare advantages. The relative importance of each area of welfare assessment is a philosophical decision that varies from person to person.

Add to this the impact that different housing systems have on food safety, egg quality, economics and the environment, and it is staggeringly complicated to compare the benefits of each housing system. It is far too simplistic to state that any housing system is inherently better than another, let alone that any of them are unacceptable or ideal. Anyone who can make this type of declaration likely doesn’t appreciate the complexity of the issue.

Mike the Chicken Vet

Tauson, R. Management and housing systems for layers- effects on welfare and production. World Poultry Science Journal 2005;61:477-490.

Lay , D.C., Fulton, R.M., Hester, P.Y., Karcher, D.M., Kjaer, J.B., Mench, J.A., Mullens, B.A., Newberry, R.C., Nicol, C.J., O’Sullivan, N.P., Porter, R.E. Hen welfare in different housing systems. Poultry Science 2011;90, 278-294.

Rodenburg, T.B., Tuyttens, F.A.M., Reu, K.D., Herman, L., Zoons, J., Sonck, B. Welfare assessment of laying hens in furnished cages and non-cage systems: an on-farm comparison. Animal Welfare 2008;17, 363-373.

Sherwin, C.M., Richards, G.H., Nicol, C.J. Comparison of the welfare of layer hens in 4 housing systems in the UK. Brit Poultry Science 2010;51, 488-499.

Wilkins L.J.,McKinstry J.L., Avery N.C., Knowles T.G., Brown S.N.,Tarlton J., Nicol C.J. Influence of housing system and design on bone strength and keel bone fractures in laying hens. Veterinary Record 2011;169:414-421.

Nimmermark, S., V. Lund, G. Gustafsson, W. Eduard. Ammonia, dust, and bacteria in welfare-oriented systems for laying hens. Annals Agricultural Environmental Medicine 2009;16:103-113.

Response to Activist Video

This blog post is one I was hoping not to have to write. In Canada, there was recently an “investigative report” on the commercial egg industry. It developed after an animal activist group took undercover footage and passed an edited video to a television newsmagazine. The resulting 30 minute show was a black eye to the professional farmers, and has caused a stir in the public. I am disappointed in the response from the industry groups to address this attack, so I am writing this blog post in hopes of doing my part. This commentary does not represent any organization, and is entirely my own opinion.

First, let me point out some of the issues that are at play in animal activist videos in general.

1) Modern farms are large. This is daunting to most non-agricultural people. Looking at a barn with 10,000 chickens is as alien to you as me looking at an auto assembly plant, or a brewery, or a company that makes computer components. The shock of seeing the alien environment is leveraged by insinuating that it is impossible to care for large groups of hens. The fact is, there are basically as many laying hens in Canada as there are people. The farms are large because so many people live in cities and towns and don’t have time or interest in raising their own food. 30 Million chickens have to live somewhere in Canada if we want to continue to eat eggs the way we do now. Interestingly, the average flock size in Canada is smaller than anywhere else in the developed world….in the US, farms are between 50 and 100 times as large.

2) Activist videos are not what they seem. No, I’m not saying they fake them (although that has happened in some cases). What you need to realize is that the activist takes video for 4-5 months, then edits the video into the worst possible 15 minutes possible. The mandate of animal activists is to stop the use of animals…..all animals. They aren’t interested in showing the truth….if false representation helps them stop a process they see as immoral, that is very acceptable to them. Think about what this means. Imagine someone secretly taping you interacting with your kids or coworkers for months, and then trying to make you look bad. Imagine going through 4 months of footage of baseball games, and clipping out batters getting hit, hard slides, collisions at the plate, then make a 15 minute video of how baseball should be stopped because it is too violent. If the people watching were from the interior of China where people are unfamiliar with baseball, what would their opinion of the sport be?

3) Farmers (and unfortunately, farmer organizations) are petrified to make mistakes in public. If you say something incorrectly and it is misinterpreted at a party, somebody might think you are an ass. Make a clumsy remark to a “gotcha” reporter, and you make an entire farming community look bad. Nobody wants to be the face on TV that makes everyone look bad (it’s interesting that the activists almost never show his/her face on the videos either). Unfortunately, the implication is that the farmers have something to hide, further shaking public confidence (oddly, it is seen as protecting the activist’s identity).

4) The “alternative” methods are always shown as a Walt Disney film. We need to house 30 million hens in Canada. If everyone doesn’t want to house 2 hens on their apartment balcony, we need people to make a living by producing eggs for the city folk to eat. To farm, you need to have enough income to pay your bills and feed yourself. The 5 hens that were shown running around the feet of the cow, on a sunny summer day will a) feed the farmer and maybe 2 other people (we will need 29, 999, 995 more farmers to do this), b) have a much less pleasant time when it is raining or snowing out, and c) have to earn the farmer $10,000 each in order for the bank not to repossess the farm. If you want to promote free-run or free-range, at least understand what a 5,000 bird flock of hens kept in that system looks like (5000 is about the minimum size of flock where a farmer can make a living).

5) It is assumed that the only reason farmers keep hens in cages is to increase profits and sate their greed. In reality, especially in Canada, there is much more profit to be made farming cage free or organic hens (see my blog post There are several reasons why hens are in cages. Cages are the housing system that result in the healthiest hens, the safest eggs, and the least environmental impact. They are the most efficient method of producing eggs, and thus result in the most inexpensive eggs for the consumer. The industry consists of over 95% of the eggs being produced in cages because that is what the consumer has demanded. If people stop preferring cheap eggs, the farmers will respond.

With these ideas in mind, there are things that happened on the activist video that needed to be improved upon. The farm had an unacceptable method of euthanasia. Their training of employees was weak in this area, and the problem was one of ignorance, rather than callousness or laziness. The method of euthanasia was actually more difficult and labour intensive than the approved, proper and effective methods. In this instance, I thank the activists for finding the problem so that it could be fixed. In 15 years as a laying hen vet, I have never seen another farm that euthanized pullets incorrectly….cervical dislocation is a very effective, humane and simple method of euthanasia that is used EVERYWHERE…..I honestly don’t know where the idea came from on this farm.

The unfortunate side effect of having large flocks (at 120,000 hens, this is one of the largest flocks in Canada) is that there is bound to be injured or escaped chicks. This is what the farmer works to prevent and address on a daily basis. I don’t work directly with this farm, but every farm I work with will inspect each of the cages at least daily, and the vast majority will inspect the barn 2-3 times per day, to remove injured or dead chickens, and make sure no birds are trapped or injured. Despite the appearance of the video (again 4-5 months worth of injuries shown in less than a minute), these things don’t happen often, and happen LESS in cages than in other housing systems. The activist stated that she saw ‘a thousand chicks die’. I don’t doubt it. Sounds dramatic. But think about 1000 chicks out of 120,000 chicks. If you have 5 hens in your backyard, that would be the same rate as 1 BIRD DYING EVERY 22 YEARS.

Is this farm perfect? Absolutely not. They need to change some of their practices. In general, they do a good job. The TV show condemns cages as a method of housing laying hens, but makes no mention of the changes that are being undertaken by the industry to implement furnished cages, which have been shown to be a VERY humane and effective way to house hens, maintaining the health and safety benefits of cages, while allowing much better behaviour capabilities and freedom of movement. Are cages acceptable? As someone who just finished my Masters Degree in Animal Welfare, I am very supportive of furnished cages, as are the ethologists I have worked with over the past 15 years. Only you can make that decision for yourself, however. What I can tell you, is that if you ask for the industry to change, it will. The housing situation right now is in place because that is what the consumer and society has demanded.

If you have any questions or comments, I will be interested in hearing them, and will respond as well as I can.

Mike the Chicken Vet

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 ( 

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… 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

Coming Out Party

I’d like to say hello to all the people who have just discovered my blog.  For some reason, I have been “discovered”, and my hit-rate has gone through the roof.  I’m not sure the source of my new-found popularity, but I’m glad you have stopped by.

Anyone who has toured the blog has noticed that this is not a “cute pictures and caption” type of site.  I don’t post as often as I’d like, but my posts are usually pretty full of information that the general public may not be privy to.  I have a unique position in that I am a full-time practicing veterinarian for professional egg farmers in Canada and know intimately what happens on the farms that produce the eggs that you find in your grocery store.  I also have an interest in backyard flocks and have an idea of the types of people who keep small flocks, and try to help them be successful in their small farming operations.  I also have recently finished my Masters degree in Animal Welfare.  This is pretty unique because I am very aware and interested in the animal welfare issues surrounding both professional and backyard flocks (yes…there are significant welfare concerns for extensive flocks as well….).

I have been building this blog for about a year and a half, and have enough content now that I think it will be of value and interest to quite a few people.  As I said, I’m not sure why the sudden uptick in traffic, but if you are new here, welcome.  I hope you find something of value, and thanks for visiting!