Q Dear Practical Poultry, I keep a few hens and a cockerel in a two-acre paddock. Recently I tried to introduce two Rhode Island hens into the flock. I noticed a few days later that one of the Rhode Island Reds had a bald patch on the back of her neck. The next day the back of her neck had been pecked open and was bleeding. Also the cockerel was always mating with her, and was paying no attention to the other birds. I separated the Rhode Islands from the rest and I was wandering why the cockerel was always going for one hen and if there was any way to stop it?

A The patch on the back of the neck is a classic treading injury as this is where the cockerel hangs on with his beak while treading the hen. With this being a new bird in a flock, there may also have been attacks from the other hens - these usually assert dominance by hanging on to the top of the head or back of the neck. Once the skin was damaged the other birds will be drown to it and start pecking at the wound. Removing the bird was the correct thing to do.
A cockerel will always pay mare attention to the new girls in his flock and, occasionally, will show this degree of attention to one hen even when the choice is large. If the other hens are not Rhode Island Reds then it may well be that this hen stuck out but the other RIR hen was not targeted so this is unlikely. I have seen a dominant hen targeted like this - one of the cockerel's roles is to maintain harmony in the flock (which is why a lot of people use an adult cock in with a pen of younger birds; to stop some-age fighting) so, if this new hen was trying to assert her position at the top of the pecking order, and upsetting the settled order in the resident hens, the cockerel may well have intervened. The less serious option is that she just couldn't run fast enough!