I have 13 hens and 1 roo. They are 10 months old, and act really good with each other, but today........ I walk in there and my Barred Rock and RIR where fighting. And the Barred rock had blood comming off her comb,and some feathers were missing off the top of her head. (they did not become Canibals.... they do not peck at blood. ) my Black red link came and broke up the fight. That one Barred rock seemed very mean and crabby today because she tried to attack my male mallard also Not all my hens are fighting just 3-5 the others are staying out of it, doing there own thing. The rooster kind of ignored it.