I have a black hen, I'm not sure her breed, but she has had an awful poopy butt for the last 2-3 years. She eats and does everything the others do. The first time I saw it, I soaked her butt in warm water, got all the poop off and put some diaper rash ointment on it. That was about 3 years ago. It just doesn't seem to clear up. She is the only one with the poop problem. You can usually smell her before you see her. You can be standing talk to the horses, take a whiff and know she's around. I don't see it as a problem, but when company comes over, I put her away. Any thoughts as to what it is? Maybe it's just her digestive make-up. I can totally relate to her because I have digestive issues myself! I guess birds of a feather flock together huh?