I have 2 roos and 8 hens. They are all the same age, 20 weeks. The hens are just beginning to lay, 3 small eggs so far. The roos have been trying to mate for about 3 weeks now. So far, no visible damage to the hen's backs from the mounting. What I'm noticing is how rough they are on the hen's combs. There tends to be blood on a couple of them each day and I noticed one has a small chunk missing from her comb. For the most part, I think the hens are not submitting to the roos and try to escape. As they continue to mature, will the roos do less damage to the combs or is this normal? Thanks!