Aggressive hen

I have a Cinnamon Queen hen who is constantly pecking and plucking the butts of my other hens. We don't have a rooster but we've tried isolating this hen and there isn't anything that will make her stop. We've had several instances of her plucking and pecking until they bleed and then all the other hens start pecking at the wounded hen. I don't know what to do, we haven't had these chickens for a year and I need suggestions. We are also a no kill household. All our hens are laying chickens. Her name is Falin and she's my favorite hen too.