My Roosters usually mates their hens in front of me.
Sometimes this is the roo showing you that he's dominant over you, & his ladies.
Often in my case, I just happen to be there when he decides to get busy.
Has he attacked you lately?
My method of raising roosters is handling them from day1 - to adulthood. Every once in awhile you get a bad seed that can't be changed. Only had two, technically 3, I have Black Silkie rooster who's a butt head. But I love him, so he's staying.