I have had the same problem. The two older girls just never accepted the 5 new ones. The pecking and chasing away from the water became too much for me to bear, so I built a second coop and keep the two aggressive ones away from the other 5. It's a drag having two coops. I let them free range...
We have 3 lovely girls about a year and a half old. Two stick together but the third has only one eye and she has been forced to keep to herself. They don't hurt her as long as she stays away from them. We have only had the for about 3 weeks. Told they are cross between RIR and White Leghorn. We...