Our chickens pretty much molt toward the end of summer or in the fall then grow back their plumage over the winter, I'm in Oregon.
We had a rooster with a bare butt recently, I found it when I was spraying one night for scaly leg mite! When the flashlight hit his vent there were a thousand little white mites running around. Gag. Couldn't believe it since I spray them every 2 to 3 weeks and give them Dio Earth to take dust baths in but I can't say I have ever seen him rolling in the dust. He is a newer rooster someone dumped, he just appeared one day, so he spends his days in the pasture away from all the other areas already claimed by other roos. My first guess would be mites?
