Hi
When we were looking at guinea pigs our pet shop was insistent that they would only sell girls in pairs or more and they would only sell boys in threes. Their reasoning was that you were less likely to have bullying or a dominant guinea pig if you had three, but everything else I've read says that boars should be kept in bonded pairs.
What do you think?
Trios are the most difficult constellation to get right in guinea pigs of all genders, ages and combinations in the first place. You end up with an outsider situation of some sort or other more often than not. Boars work best in personality matched pairs or in large bachelor groups with plenty of space to get out of each other's way.
In fact, bullying and fighting is much more likely in trios, as you rather inevitably end up with either one dominant boar waging war on the other two or the two strongest ones turning onto the weakest once they hit the big hormones. If you have bought three dominant boars, you are likely to end up with three singles that won't go with any of the others. You need three very laid-back baby boys to have a chance of them making it without fights or bullying. Lack of space in too small cages will exacerbate the problem, as boars are wired to get out of the way if they cannot compete. The key to any successful boar (or actual guinea pig bond) is character compatibility, i.e. the right mix of dominant/submissive personalities, not age or being related.
In same age sub-adult boars, the fall-out rate with trios is about 90% before they reach adulthood. Testosterone output is at its all time highest during the teenage months between 4-14 months; it starts when the testicles start descending at around 4 months of age and are the worst around 6 months once the testicles have fully descended. These are the typical ages for boar fall-outs with trios and couples that are not character matched. There are some tricky periods later on, but they don't lead as often to splits as the worst personality clashes have long since happened.
Our forum has been going for 10 years now; we are one of the busiest and longest-lived guinea pig forums internationally and the largest UK forum. In that time, we have seen hundreds of boar bonds pass through here, so we can claim some experience on that score.
You can find our forum littered with people in trouble over boar problems. We really noticed it on here once shops started selling trios; we suddenly got lots more posts over fighting and fallen-out teenage boars.
By the way, boar quartets have a fall-out rate of nearly 100%; they usually work only with a disabled/carer pig situation or with old boars where the testosterone output has mostly ceased.
Boars, sows or mixed pairs; babies or adults?
Boars: Bullying, Fighting, Fall-outs And What Next?
Boars: A guide to successful companionship.
Cage Size Guide