Hi all, I have a chicken that is constantly bald around the tail feather area. It often looks very red and swollen. There are only three of them and there is an established pecking order. I have had these chickens a while now. I never notice the other two pecking her, and the only time there is any pecking is when they eat in the morning, this is not aggresive pecking either. There are no feathers in the coup and she does not seem to be pecking herself. They are all laying eggs daily, and there poop is normal. The skin looks very sore, and there are no signs of mites. Any ideas?