I have 12 white rock hens, all 20 weeks old. There is one that is bigger than the other ones. I went out this morning and her butt was all bloody and the other hens won't leave her alone. I am assuming that it was the other hens pecking her and making her bleed. I took her out of the coop and put her in a seperate pen. Is there anything that I can do to stop this from happening again? This is the first time I have had any problems. I don't want any other hens to be pecked at.