Oh, don'tcha just hate that?! I have a Polish cockerel who has started doing that, and he tries with the younger pullets who are nowhere near being ready to mate. They scream like he's some sort of rapist! Poor little girls........
He's really frustrated because the one pullet who is the same age as him will just scream and run away, so he takes it out on the younger ones......
I feel like putting him in a "time out"!