My daughter has four one-year old chickens (1 hen and 3 roosters, so much for straight run) plus one Peking Duck. We have 13 pullets ready (10 weeks +) to join the older chickens. The coop was plenty big enough, but I wanted to increase the run size before I added the new chicks. We now have a two stage run. As I read about on BYC, my plan was to let the pullets settle into the coop and at sunset let the older chickens in. Then the following morning watch how they interacted. I jumped the gun on that yesterday and had the pullets in one stage of the run and the older chickens in the other stage. I had done this previously using chicken wire, just so they could become accustom to each other. Well, when I opened the door between the two runs, they started to intermingle just fine. After a short time the older hen started to jump on the younger ones. Is this normal, maybe just establishing the pecking order? How long will this happen. Should I be concerned? thanks for your inputs.