Good morning, and thanks for reading this thread, We have 15 hens of various breeds, and one rooster. Last March they started looking a little rough. At first we thought they were molting. Eventually some filled their feathers in, but a few had large patches of bare skin. Never any sign of new feathers growing in. One has large areas of broken feathers on her back. Several have few if any feathers on their neck and head. Also large bare spots on their lower back, including the base of the tail, and including most of the tail feathers. I eventually read a post about mites, and thought this may be the issue. About six weeks ago we cleaned out the coop thoroughly. Then treated all the chickens with the dust Big R recommended. We repeated this process weekly for a total of three weeks. By the second treatment we had new feather growth on most of the hens. They looked SO much better! The hen with the completely bare chest now looks completely normal! However my EE hen with bare head, many broken back feathers, and bare spots on the bony areas on her wings has never improved. Now we are noticing recurrent bare spots on several of the hens. Their appetite has slowed down again. I feel this may be a sign of mites that live in the wood. Or such a severe mite problem that three clean out, and dustings just weren't enough. Yesterday we cleaned out the coop, and sprayed with a chemical that Big R recommended, placed heaters and fans to get the coop dry. It was something to catch everyone that got caught out as it started to get dark. Their coop was not completely dry. I left heat lamps on to continue the drying process over night. It is above freezing here, but just barely. Then we re treated with the dust. My question is: do we need to spray the wood weekly for three weeks as well? We will change the bedding, and nest box straw, and re dust weekly for four weeks total. But if we get the expected cold weather it will be very hard to get the coop dry. The coop is three years old, and made of cedar. The floor is linoleum tile. We use a deep bedding method with pine shavings. We feed feather fixer with mite prevention. Thanks again for any help. It can get really cold here. Last year we lost a hen to frost bite. I would like to give them the best chance for a safe comfortable winter.