I'm not sure what it is but my Rhode island reds have never been mean or aggressive towards me or each other until I put my two ameraucana babies with them.they have a new house and run more than enough for all of them and they are still acting like butt heads. All they do is chase the babies around and won't let them eat and they are very noisy. After I put the babies in they quit laying eggs also. I have maybe one or two that lay NOW but not before. Not sure what you do any more except start eating more chicken if it comes down to it.any ones help would be awesome.