I think my chickens are killing each other

[dalhartchick]

I am raising Buff Orpington and our hens are litteraly eating each other. Every one of our hens have no feathers on there back and we have reasently had to bring in one of our hens because she has been eaten to tgw bone under one of her wings, we have doctors her and she is doing better. I understand hyena have a pecking order but once they see blood they will peck at each other until they die.