Yep thats a roo. Roosters will mount each other to show dominance over another.He is the one in the back.
This is him in the front. You can see how the other boys behind him are a lot more developed. I just couldn't pin if he was a boy for sure. He is now with 10 hens and 1 rooster. The rooster appears to leave him be for the most part. I have seen my rooster mount him before so that's why I was confused. He is best buddies with the chicken in the top picture. They sleep in the same box and everything.