My white leghorns just started laying Sat. and already I seem to have a problem. While one is in the nesting box trying to lay an egg the others take turns pecking her and trying to rip her comb off. I have had to remove one because she is bleeding everywhere which makes them peck her worse. I have 10 chickens and 3 boxes so they have other boxes that are empty. They will peck all the chickens in the box, but only one they are violent enough to injure. What can I do to make them stop?