I have two coops, one with a rooster and three hens. One of the hens has been sitting on five eggs for about two weeks. I wanted to add two hens from the other coop to this coop. These new hens are three months old and just about the same size as the others. I put one in and the rooster and two hens attacked it. I waited till they were up in the coop and on the roost to do this. I put the new hen on the roost and the hens kept pecking at it until it jumped off the roost, then the hens and rooster were all over it. Is this because there is a Brody hen in there laying on eggs and they see the new addition as a threat? Both of these coops are right next to each other. I didn't add both new hens, after I put the first one in there,I didn't get a chance to put the other one in there. I removed her after only a couple of minutes. Please advise as to when I can add these new hens.