Agressive Chickens- New flock

My chickens are very agressive! My rooster is biting everyones heads and making them scream! It's blood-hurling! There is one chicken I am not sure about because it bites everyone and even pulled a father off my rooster! I thought the rooster was going to get mad but he didn't! He just yelped and went back to eating. We also have some new chickens who are a year older than my chickens. My friend is moving so she gave us her chickens. The bad part is that we already had a rooster and they gave us a rooster and 2 hens! The roosters fight and my poor little rooster gets hurt. He doesn't bleed or anything but his feathers come off. My hens chase the new ones and this one chicken always goes over to where the new chickens play and chase them! I always have to go over and steer him back to his own group. So I have 8 chickens total now. 2 roosters are too many. The new hens lay eggs and like going into my chickens coop and laying in there. My chickens always go into the coop when they see them going in there and chase them away. I clipped all of their wing and a new hen is kind of sliding everywhere when he runs and stops too suddenly. What should I do? Need help badly. I made the new chicks a new coop but its a little tall so we are shortening the legs.Please reply back with help! Thxs in advance!!