My son has a black frizzle roo and hen. They had been penned together but then she decided to go broody. Because of the genetics thing we couldn't let her hatch out her own eggs but gave some of our other hens. She was penned up separately. He was now alone. Because he was all alone we felt sorry for him and let him free range by hisself. The others were penned to keep the from eating the apricots at this time. He got mean. I played rooster football a couple of times and played at being a monster chasing him. My son loooves this rooster but doesn't hold him or anything, so I had to try and fix him. He would try and fight through the fence with the other chickens. I decide to build him his own house and large pen. When it was done, I move him in alond with 3 hens. After 2 days ALL of his bad behavior stopped!!! I was amazed. It turns out that his only problem was hormonal frustration because he did not have any girls at all. Your roo may need a few girls to settle him down. Fighting with your other roo is normal. He's trying to be the alpha roo. I would try giving him his own space with his own girls and see if that helps. Cochins are one of the most laid back breeds.
ETA: Even though your polish girls are not laying, they can still be put in with a roo. All of my roos and hens grew up together. They were not separated until the girls layed.