I have a bully hen who keeps mounting my other hens like a rooster would do. I wouldn't care, except she pecks at them viscously and pulls out their feathers as she does it! I didn't get a roo purposely because I didn't want my hens to feel bullied...but now I have this problem hen who has assumed that role. Is this normal? I don't suppose there is anything I can do to break her bully behavior?