It would be a big problem. You can only keep boars in pairs. Adding more pigs to a boar pair will result in fights.
If you want more pigs, then having a separate boar pair that live totally separately is the only way.
Boar trios (and more) have a 90% failure rate. At best the new pig won’t be accepted and needs a new friend (so you end up with two pairs). At worst, adding a third ruins the original pairs relationship and then all three need to live separately, each needing a new friend so you end up with three pairs.
Adding More Guinea Pigs Or Merging Pairs – What Works And What Not?
The only way to successfully keep a boar group is to have at least 10 guinea pigs with a very large enclosure amounting to at least a square metre each. But even then it requires huge amounts of experience plus loads of separate cages in case if all goes wrong.
[/QUOTE