Hi! My son and I started raising chickens April 2009. This year, we are noticing that a few have large patches of feathers gone off their backs. Some have a few gone where the roosters have mounted them, but a few have a lot more gone on their lower backs. What is causing this? Is it anything with diet? They are still laying as great as before. Is is hens pecking each other? The gnats are horrible right now and the chickens stay inside voluntarily to avoid them. I didn't know if maybe that started the pecking of each other. It's not all the hens. Just a few of the golden comets. Thanks for any help you can give me.