In my personal experience growing up around chickens, when we had more than one rooster, they would fight to determine dominance, but so far as I know, we never had one actually kill another. As with most similar confrontations, one would withdraw, and that would be the end of it. I know that fights to the death (outside of a pit) do happen, but it never happend with ours.
From what I’ve picked up in docs, news blurbs, etc., it’s pretty commonplace, if not the rule, to put metal spurs on one of their feet. Why? Is that to ensure that the fight will be over pretty quickly because one of the birds is pretty much ensured to get slashed/skewered?