18 week old cockerel being aggressive with just 1 hen

[Not so Feathered friend]

Hi everyone, we have a flock of 11, 10 girls and the big man, Pickle. 9 of the girls are 10 months old, the last girl and the cockerel were hatched using our broody hen and are about 18 weeks now.
Over the last couple of weeks, Pickle has started crowing (some nights from 2am!!) and has been mounting the girls. The way he mounts can look a bit aggressive but there is a definite difference in how he is with just 1 of the older girls, Whimpey. I noticed it yesterday and just thought he was doing his usual but he wouldn't leave her alone and was biting and pulling on her comb and he was just standing on her, not mating her. I went out to see what was going on and when I picked her up her comb was bleeding and its very scabbed so it must have been going on for a few days. I have kept an eye out since to see what's going on and she stays away from him as much as she can but if he sees her he charges at her, he will even leave his corn to get her.
We don't know what to do, wether to wait or to rehome him. I posted a few weeks ago because he is roosting in a tree right outside my bedroom window and no matter what I try to get him in the coop, he goes straight back into the tree so my lack of sleep is also having a baring on my decision. He is not aggressive with us so I would be sad to see him go but I absolutely love my girls so I'm scared for Whimpey as I can't watch them all the time.
I am so grateful for any advice

 

[1cock2hens]

personally I would pen him by himself for a while and wait for his hormones to balance out or just get rid of him. probably get rid of him honestly if he were mine.. good luck

 

[townchicks]

I agree make him his own pen, that will solve both problems, then he will have no choice than to sleep in a coop.

 

[chickens really]

Hello...Remove Her from the flock. She isn't submitting and watch him. He might need to be removed too...
Hmmm...I got rid of all my big chickens...Im Chickenless.
I'm getting Silkies and if they attack each other then they are gone too. Birds should be fun like my Call Ducks..

 

[Hensndoes]

at 18 months she is either just about to lay and hasn't figured out the breeding protocol yet or he is just a jerk. Or both. Or whimpy is a boy and won't be figuring it out...either way Mr. Hormonal needs to cool his jets.