I have four cochin chicks. All somewhere around 3 months. One is smaller then the other 3 and it seem healthy. I noticed tons of little black feathers around the floor, and in their cage so I just assumed she was molting, but then I noticed her perching and all of a sudden, the little cockerel jumps up and starts pulling feathers from her chest. I haven't had to ever deal with bully chicks so im clueless on whether I should or shouldn't separate her.