Dealing with an abusive Rooster

It's been quite a few years since I had chickens but after recently buying a small farm my Son talked me into it. I started out only wanting a few Barred Rocks and now we have 13 Barred Rocks(11 hens 2 Roosters) 12 New Hampshire Reds purchased as straight run and 4 appear to roosters and 10 mixed black bantams. The bantams were Tractor Supply specials and although they all appeared to be the same breed I'm now sure I have at least 3 if not 4 different breeds about half of which are roosters. The bantams are about 2 weeks older than the others which are 6 weeks old. I intended to keep both barred rock roosters and at least one of the New Hampshires with hopes that the primary breeder would be a barred rock.

Well a few days ago one of the barred rock roosters started picking on the bantams excessively, he is the Rooster I'd like to keep but don't want a bully. He pecks at the back of the head mostly and it seems to really hurt them and he singles out the bantams in general not caring if it be a hen or a rooster. The pen they are currently in is about 160sq.ft. areas of bright and dark lighting, plenty of food, water and clean bedding. I am just finishing the outdoor run and it measures 25'x40' attatched to a 12'x16' coop the birds will free range daily also. Because I want to free range them a good bit and we have so many predators I was planning on several roosters for patrolmen. I was hoping that being raised together would keep relative peace amongst the roosters. The enclosures also seem plenty big for a peaceful flock.

So to get to the question, would a bit of solitary confinement help cure this largest Barred Rock rooster who just happens to be the best looking of the bunch also. Seems if I would cull him from the flock I would be getting rid of the best genetics.
Any thoughts or suggestions would be greatly appreciated.

Dave