I have been raising chickens for years and have never had this problem before. I have a small flock of banties that I raised together. I have given away some of the roosters I had until I now have a white silkie and a buff Japanese bantie roosters. I have a white silkie hen, a buff japanese hen and three sebright hens. Recently, I noticed that when one sebright hen tries to come out to free range with the other hens he chases her back into the coop. He has tried to mate with her a couple of times when I was outside with them before this behavior occurred. He was very mean to her compared to the other hens. She was crying out as in pain. She got away both times I was there and flew up on my shoulder. Now, she stays in the coop up high where the rooster can't get to her. The funny thing is that when the brood is closed up or running in their pen everyone is friends. I have even seen her roost next to the rooster. I have never seen him be mean to her or mate with her while inside the coop or pen. It always happens when they are let out to free range for grass and bugs. I feel sorry for her because she can't get to the grass or bugs. I don't know what to do. Has anyone ever had this happen to them before?