I think some of the members here need to get up off their high horses.
You were previously given advice about NOT housing three boars together, by some very knowlegable and experienced people. If I remember rightly you didn't even WANT boys - why get another?!
Even if other people have given advice, it is only just that. Advice. Sure, someone can be knowledgeable or experienced with something, but that doesn't give anyone a higher status than another member. Someone who watches cooking show after cooking show, and does a bit of cooking themselves doesn't make them a chef.
If you're going to give advice, go ahead, but don't force your opinions on people while you look down upon them. That's the last way you are going to get your message across.
I hope you have the room to house three boars separately, and the money to be able to afford to keep three more pigs, to bond them with into new pairs, as this is a real possibility if you try and add another male to a bonded pair.
I also hope you have plenty of cash set aside for the resulting vets bills if they do decide to fight - razor sharp pig teeth can do a lot of damage very quickly.
If you are really a guinea pig enthusiast you would know the kinds of conditions that they live in at pet shops, and they are far from your idea of a 'perfect home'.
No one in their right mind would spend that kind of money to have 3 guinea pigs kept apart, unless they like to throw money around like it's nothing. I think it would just be cheaper to get them euthanized at the vets, if worse comes to worst.
Anything is possible, and the only way to find out is to try it.
We can all find a site somewhere that will tell us what we want to hear.
Does anyone here even have any actual evidence backed up by a credible source?
If you want to go ahead and try and bond them as a trio, then we wouldn't be doing our "job" as caring piggy people without warning you - at the end of the day, it's your decision.
You can give your advice, but there is a certain point where you start to come off as if you are better than other people, and that doesn't help your point at all. If you want to be helpful it's just as easy, if not easier to do it nicely.
I had a trio of boars - they lived happily together for 2 and a half years. Then for no reason, decided to fall out and start fighting - it can happen at any age, for any reason, so just because they seem happily bonded to begin with, doesn't mean that it's going to remain that way.
Finally, if you're unsure of the sex of Mr Moo or ANY of your pigs, get them checked out by a vet.
You're helping both points here. You're saying that it IS possible to have three males together. You also said, for no reason they started fighting, but do you keep an eye on them 24/7? As the saying goes "You don't know what goes on behind closed doors". There might have been something that DID happen that caused them to start fighting.
The only way to know is to try it out. Just because one persons experience is bad, doesn't mean that it will be that way for everyone.