What? Where you meaning me joking or op? I know chickens killing or fighting each other is common, its what the stew pot is for.All joking aside, it is a physical impossibility to prevent a chicken from harming another chicken if both chickens are willing to fight and they are able to get close to each other. It can't be done other than by chopping off one or both chickens' heads. It should be apparent by now to anyone who reads this forum because of all the posts from traumatized chicken keepers worried about their hens or roosters "bullying" each other.
But you shouldn't make them start a fight**(this is for op)**...how would you feel being put into a ring to be intentionally ****** off and fight to the death? Because that's how the cockfight ring goes, only one makes it out, and what if its your rooster? You would have wasted all this time making them pets and getting food and learning how to properly take care of them on here for nothing. Roosters can serve purpose, eat them or keep them as a pet like you would a duck, they can be great as both rather than wasting bets on a ring where they fight to death for entertainment.
I apologize if I seem over reactive about this but cockfighting rings have always confused me and it never seems worth it, its like when people fight their dogs.