I have 9 adult hens which we bought from tractor supply as pullets (not sure of the breed they look like Red stars but larger) in May so they are about 10 months old now. They are so aggressive I don't know what to do with them. They are not aggressive with me but they are with my cats, other chickens and the ducks. When we got the chickens we had also gotten ducks at the same time and they tolerate each other pretty well. But we had taken in 2 new ducks and had them separated in the pen for about 2 weeks and then introduced them to the flock. They did really well with the ducks but my hens would see them and just attack them and ended up killing both of the ducks. Now I have 13 Red Stars and one Jersey Giant pullets, they are about 12 weeks old. I ordered them as day old chicks and at 4 weeks I put them in the adult birds house but separated until about 2 weeks ago. So they were around each other for 6 weeks before I put them together. At first the Adult Hens beat up all of the babies, but now they are leaving the red stars alone and only going after the jersey giant, who is so gentle and won't fight back. It's not just 1 or 2 of the hens it's all of them, they see Giant and just go after her and theyll trap her in a nest box or a corner in the pen and will just beat her up. I am afraid they are going to kill her, I do break it up and make them get away from her but that almost seems to make it worse. I don't want to get rid of Giant she is such an awesome chicken, but I don't know what to do to stop the 9 hens from beating her up all the time. Please help!