I have two ducks and an entire coop full of hens. These two ducks keep on ganging up on one of my little birds, a Rhode island red named Rossetta. They chase her around the coop, pulling her feathers out. I've tried separating them and then slowly introducing them back in, and chasing the ducks off when they start attacking. Nothing I do seems to stop them. I would really rather not have to keep the ducks and chickens separated full time. Anyone have ideas on how to stop the bullying?