I'm new to raising chickens. My BF and I have 22 chickens, and possibly 8 of them are roosters. We hatched them ourselves and they are 11 weeks old now. The more dominant of them, a barred rock, is bullying our smallest RIR hen, Peanut. We mostly see it in the a.m. when we open the door to the coop to let them out. I noticed today when I let them out that Peanut, who normally goes right out in the morning seemed to stay inside the coop. I coaxed her out and as soon as she got outside, the rock went right for her. He has bit her before but I stopped him today before he could do anything to her. What should we do? Other roosters have picked on her before but not as consistantly as the rock. Also, is it possible that they could be trying to mate because i have seen them do this to other hens as well?