I wonder if maybe your cockerels are picking on each other? I know my EE cockerel started trying to mate and crowing at 14 weeks but the pecking order squabbling was going on with all of them before that.
Camo was in isolation, letting his poor tail heal, when Harpo was attacked. They tore up Harpo's left wing pretty bad. Camo and Harpo of two of the shyest of the group. They never are involved in squabbles over food or roosting space. They pretty much just settle where ever they are allowed.