Why am I thinking wolf tooth? Strangles would be bad, and I hate to say it paint gurl but are you sure your horses didn't have strangles also? Just because your horses natural immune system took care of it, doesn't mean you weren't miss diagnosing the situation. Anyways, if its a wolf tooth its a very noticable bump on the jaw behind the chin, but I thought strangles was much closer to the throat, not on the jaw, could be wrong though, not an expert. Also 6 is old for a wolf tooth, but I don't think it's unheard of.
Troubled TB ~"A thorn by any other name will prick just as deep." @-'--,---