I have a rooster that is probably just over 2 months, maybe 3 months now. I rehomed the hens he was with. He joined my older hens. He was trying to be friendly. The older hens were not interested. He would try and pick up a piece of grass, or if he was getting beat up, he would try and get the hen to look at a wall..."This wall is really interesting..."

They won't except him until he is 6 or 7+ months old. So for now, I would keep him separate from the adults until he's grown more.