Please don't take this the wrong way Vi, but boars don't normally end up fighting, well not in my experience anyway, lol. I have more boars than sows and not one of them lives on their own ;D In the past five years I have only had one really difficult boar that wouldn't live with anyone. Neutering is a really good idea though as there is nothing better to see than a very happy boar, if you get my drift, lol. Just please remember that with any surgery there is a risk, even if it is a small one. Be sure to find a very compentent cavy knowledgable vet if you decide to neuter ;D