Q: I have recently adopted one female and two male guinea pigs. They are all around 2 months old. I am waiting for the boys to be the right weight to have them fixed. I’m too scared to have the female fixed in case she is already pregnant. Once the males are fixed, will they leave my little female alone? They currently follow her all over the place. I would like to add another female to the group once the boys are fixed, but I don’t want to do that if it’s going to cause fights. They have more than enough room to roam and play in their two-level, split-level “home” with plenty of hidey-holes.
A: Having a male guinea pig fixed will not change his natural propensity to want to mate with the female. It will only insure that there is no conception after the act. In the situation you describe, having only one female who will cycle every 17 days means she will not only have the unwanted advances of one male, but she will be chased around constantly by two. This may be too much for your little female, it would be too much for most human females.
If you could separate your males and have two groups, one fixed male and one female each living in separate housing, that would be much healthier for your pairs than the stress of them all living together as they are now. One male and one female living together has been an ideal configuration, or having two females to one neutered male is alright as well. Two neutered males and one female is a very stress-filled environment.
More than likely you are right to assume your female is pregnant. You should house her separately to insure a healthy pregnancy and delivery. This will also insure your female does not become pregnant in the first 24 hours after giving birth, as this is when the males will demand to mate with her, possibly causing injury to the pups, and forcing her to carry another litter while trying to raise the one she already had. It would be a grievous hardship to both mother and pups.
Female guinea pigs can become pregnant as young as 4 weeks (1 month) old. Though how viable the pregnancy would be is questionable. No matter what, it is undue physical hardship for her to carry so young or even abort at that age.