We neutered our male as soon as we found out he was not female and had impregnated our other two pigs, who were in fact female. At our vet's suggestion, we kept him separated from the girls. However, in hindsight, I think he would have been fine with them.
We had six babies between the two moms, and two of those were male. So at 21 days we stuck the male babies in with the now-neutered dad, an he was great with them. In fact, because the boy babies had an adult with them, they didn't cry for their moms like so many do when they are forcibly separated -- they sound so pathetic when they do that and it feels so cruel, but it has to be done. But because they went in with dad, they never cried. They did try to nurse from him a few times, but he put a stop to that, lol. He ended up being a great dad and the male babies learned how to eat pellets, drink from a water bottle and all sorts of things from him.
We ended up re-homing the two male babies and dad went back in with everybody else at that point. He's been with them ever since.
As for who is top pig, it's the pig the others defer to. If you see two pigs competing to see who can lift their nose into the air the highest, that's a dominance spat. Whoever has the highest nose wins. The loser will duck back down and turn away or defer to the winner. Mounting (in females) is a more intense way to show dominance.
My herd of six pigs has shifted status levels quite a bit amongst all the pigs over the last several years. They work it out. It has no bearing on you or what you do with them. It is just how they work spats out among themselves.
- And got the T-shirt
His surgery was successful, but it did have a minor complication in that a hematoma developed and the vet had to go back in surgically to remove it. If you decide to neuter, then make sure that only a vet who has a LOT of experience neutering guinea pigs does it. Guinea pig neutering is a more delicate procedure than a cat or even a rabbit.
Neutering will not change their personality, their sex drive, or their propensity to squabble. And they WILL squabble when they get into their guinea pig teen years, which is about 6 months to 18 months old. They will fight more during that time period, which is why boars need a bigger cage than sows do.
That said, the advantages of neutering (and we neutered ours at about 5 or 6 months old) are:
They can be housed with females in the future (though not together; two boars with any number of sows will NOT work)
They will not grow as large as intact males if they are neutered young; they will instead grow to the size of a normal intact female
They will not have a testical sac to drag along the ground which picks up "stuff" (hay bits, poop bits, bedding bits, etc.) and so they don't need to be cleaned out much at all (I think we clean ours about once a year)
Cleaning out an intact male would need to be done fairly regularly and involves putting lubricant on a Q-tip and swabbing around in their anal cavity until no more gunk comes out. It doesn't hurt the pig, but they don't like it much.
The risk of complications from surgery is the biggest drawback. Some pigs do not tolerate anesthesia, and you won't know if your pig is one of those until it's too late. That is why that in spite of the advantages most owners don't neuter unless they plan to hosue their boar with females in the future.