Is our roo just getting his hens in line????

Our roo is 12 weeks old and for the past two days he has been really rough on his girls.
When I used to open the run door for them they would all come rushing out.
For the last two days he comes out first and then if one happens to run out past him,
He gets really mad and pecks them on their necks. At first we thought he was trying to mate.
He is also the last one in at night and we always go check on them and shut the windows around 10-12.
He is always on the floor or on the bottom of the roost. I see him make calls during the day and they all
come running, one didn't run fast enough and he pecked her good. Is he trying to get the chicken yard in line or what? Could it be possible that he would be trying to mate at 12 weeks. We have 26 girls and he is the only roo, we are hoping that he can maintain some control over them. We started off with what we thought were 27 girls and when we started seeing the changes in his appearance we realized how lucky we are. We have left him alone thus far but when he got so ruff when one of his girls at 12 weeks he got a bowl of water thrown on him. That was all we could get to at the time as they were in the run. Any opinions on this matter will be greatly appreciated....