You have to stay one step ahead of roosters from the day they are hatched. That is just the way roosters are.
I just got rid of two roosters, one human aggressive, two just an extra that was aggressive to other roosters. What I learned from my years of experience with roosters is 1) when they start being aggressive,it only gets worse 2)Aggressive to humans does not mean the rooster is going to be a good flock master, it means you can never turn your back on that bird no matter what. 3) When he is gone, the stress in the flock will decrease emensely.
I knew I was going to have to get rid of the human aggressive roo. I seperated them from the rest of the flock thinking they would settle down. They didn't. The day rooster 1 grabbed skin on the side of my knee and twisted leaving a puncture wound and a bruise, I knew I was out of options and he was out of chances. Rooster 2 would be alright as a flock master in the right situation.
I was lucky in that I was able to pass them both on to an Amish neighbor who was glad for the free meal and new rooster to breed his hens for him.
Our remaining roosters so far are good boys. They may get a little attitudish with me but there is a line in the sand with them. If they get too close, I walk towards them with purpose. If they try to mount a hen in my presence, they get knocked off by me. (Funny story. One night I was putting water in the coop for them and the beta roo, a Buff O, mounted a hen right by my elbow. Without thinking, I asked him if he had a death wish and shoved him off of her like the alpha rooster would do. He spun around at me and his whole body language was a cross between "What'd I do wrong?" and "Whow, you are big for an Alpha rooster!" He squawked at me a couple of times just for appearance sake and walked away.)
Too many people try to make pets out of roosters. I try not to. I love our boys but I do not try to pet and cuddle them. The hens are around for that duty.
My best advice is, as hard as it will be, get rid of the alpha rooster before his behaviors have a chance to get worse.