I have 2 hens with bare spots on their backs then one that that has bare spot on her back and her butt is bare. They all act fine, eat, drink, lay. They are cooped up with my roo. I keep them in the coop because I think it's too cold for them (teens and 20's with snow and winds) I have been reading post after post after post. Sounds like it could be from roo or it could be mites. I have not dusted these guys for the reason of not being able to find food grade DE. Can you see the mites, what would I look for? And about Sevin dust, this is ok to use and still eat their eggs? Help the fairly new chicken mom.