This is one of the more popular articles on controlling aggressive roosters:
https://www.backyardchickens.com/articles/beekisseds-rooster-speak.73664/
This is one of those hot topics where you will get a very wide range of opinions on what to do with this guy. Lots will tell you to put him in the freezer. If you have small children around, I am one of them.
Otherwise, you can try to rehabilitate him.
Good luck.
Yes, I have read beekisseds-rooster-speak's method, and it might work for you.
However, there is more than just one way to train a rooster to behave.
I show chickens, and this method would not work for me at all.
When the judge picks up my bird from the show cage, I want the bird to be cooperative and quiet. The judge is going to turn the bird in all directions to get a good look at him, and I don't want my bird to fight the judge or break feathers trying to get away. As the old timers say, a rooster who acts like a number 2 will never be a number 1.
To prep my birds for show, I bathe them and groom them, trim their nails, and handle them like a judge would handle them. I also give them treats (cat treats work great). I spend time stroking their combs and wattles with a cloth that has a little oil on it, to make the comb and wattles look red. Chickens know when they are being groomed, and they know it's friendly. I carry them around for some of my chores, and I wrap my arms around them if they are scared by something. I know that when I carry them onto the show floor for the first time, the noise from all those other chickens and people will scare them, so I practice with them and say the same things to them that I will use to calm them down at the show. (I use just a few phrases with them so they will sort of recognize them, like "You are my chickie." My dad used to say, "Don't worry, nobody else will eat you but me.")
For a rooster or cockerel who can't seem to get it that I am on his side, I put him in a smaller cage by himself at my shoulder or eye-level, and make a point of talking to him at least daily. I open his pen to replace his food and water, and offer him food by hand before I pour it in his feeder. If he still reacts badly by biting or trying to use his spurs, I take him out of his cage and hold him snugly in my arms while walking him around. If he is still fighting, I gently push his head down, and hold it there for a few seconds. When he raises his head, if he still tries to bite or fight, I hold his head down a few more seconds.
Keep in mind that physical discomfort can make a roo cranky. Spurs that are too long and make it hard for him to walk or mate can be annoying, as can bits of string wound around his foot or a chunk of dirt in his feathers that he can't easily get out. Also, at dusk and dawn roos are naturally more defensive, even a roo who might normally ignore you. Also, most roos who have a flock of hens will appreciate it if you take them aside and give them the food first, so they can call the hens themselves. Even if you first offer the food bucket to the roo for him to sample, then pour it out for all, the roo will see himself as the provider, and notify the hens accordingly.
There will still be a few roos that stay mean and sometimes sneaky, too. If they are good breeders I may still keep them, but in a more restricted cage, so they can't hurt me or anyone else.
