So here's my roosters tail feathers. All the skin around his tail nub looks chapped and bloody, but this patch is the worst. At first I assumed this was stress-preening as we've been having to keep our birds inside because of the recent weather, but there was no blood on his beak this morning and his tail was fine yesterday. I've checked for mites and he has none; he still eats, drinks and dances around the hens. Advice?