I have started posting a few excerpts from my upcoming book here on the Vegan Next Door’s blog, so you can get a taste of what will be in Vegetarian to Vegan. As I mentioned in the last post, I am digging in my heels with publishers who are requesting I take all or most of this “disturbing” information about factory farms out of my manuscript. I keep saying that if I take it out, how will anyone be convinced to give up dairy and eggs?
So, here is a short excerpt about a specific type of osteoporosis that happens to egg-laying hens (but not chickens raised for meat). I’ll publish a few more of these excerpts in the coming weeks.
Cage Layer Osteoporosis
Broiler chickens (raised for their meat) have been genetically bred to get so big that many of these chickens have broken bones in their feet and legs because they are not strong enough to carry their weight. Interestingly, laying hens also have problems with their bones breaking, but for a much different reason.
It requires a lot of calcium to produce eggs, and laying hens are bred to make far more eggs than they would in a natural environment. In fact, factory farm hens are genetically and physically manipulated in many ways to lay eggs all year round instead of seasonally, which is normal for them. This excessively high level of egg production requires that calcium that would normally go to the hens’ bones instead get used for egg production.
The combination of this high demand for calcium for egg production and the fact that the hens get no exercise leads to a painful condition known as cage layer osteoporosis. Like osteoporosis in humans, cage layer osteoporosis is a chronically painful disease that leads to brittle bones in chickens. These brittle bones are highly susceptible to breaking. One report found that keel bone fractures were nearly five times more common in battery cage hens than hens from other housing systems.
 Sherwin, C.M., Richards, G.J and Nicol, C.J. 2010. Comparison of the welfare of layer hens in 4 housing systems in the UK. British Poultry Science, 51(4): 488-499.