There is no better breeding ground for disease than a factory chicken farms. Put tens of thousands of birds into a single poorly-ventilated barn – all birds that have identically bred to grow very quickly to gargantuan size with a minimal amount of food. When one bird gets infected the virus can very quickly race through the entire population with nothing to stop it. And this is what is happening in hundreds of CAFOs around the world.
In one example, more than 900,000 chickens were hurriedlyslaughtered after the H5N8 bird flu virus shot through southern Russia. Worse, in this case, five workers also became infected, and while they all recovered, the incident showed that H5N8 can jump the species barrier. There is no reason to expect that this couldn't happen again and perhaps far worse next time.