I combined my pullets with my year-old hens and rooster. The rooster has taken to the new hens and the pecking order has changed to where the new girls have killed one if the original girls , the rooster won't let the original top hen even eat and has nearly pecked her to death. I have had separated all but two of the original hens. Why would this happen, I let everyone get to know each other by free ranging together before combining the coops, I did wait till they were 4 months old before combining the flock together completely at night but they were together all day without any problems. Any suggestions are greatly appreciated. The new birds are RIR a red comet, a salmon faverole, and a black Astrlalope the Roo is also a black astralorpe. The older girls are RIR, barred rocks and , black astralorpe. Theykilled one of the barred rocks already. They are in separate coops now.