Sounds like it's time for chicken soup, chicken stew, chicken gumbo, chicken salad, chicken enchiladas, chicken sandwiches.....
In my opinion, if you don't want them to have access to your birds, you're going to have to stop free ranging. My guess would be that even if you adopt one of these feral roosters, if your chickens are free ranging, you will still have rooster fights because another one will come along wanting breeding rights to the hens and take on whatever breed of rooster you have as your flock master. It's only a guess, as I am not in your situation, but that's what roosters (well, males of any kind of animal, really) do. They take on other males to win the rights to the females.