Neutering/Spaying Testicles

I think neutering of males usually isn't done until 4-6 months old. Most male guinea pigs show signs of testicle growth before that point, but it can take a while for some testicles to descend.

Good luck with the neuter. Just out of curiosity, how come he is being neutered?

@CavyMama he is getting neutered because he is a foster guinea pig through the RSPCA but I am going to adopt him afterwards.

My vets like to wait until they are at least 4 months old.

@foggycreekcavy they said they would do it when he reached 800g and currently he is at 680g so they said to wait another month so he will be 4 months by then.

Just a question about weight and size is there a way to tell if a guinea pig has been stunted? We think he had scurvy when he was 3-4 weeks and was malnourished because of broken teeth and a bad home so we were wondering if he would ever reach the 800g weight anyway? If he doesn't reach that weight will they still neuter him because he will still be older?

Occasionally there are "runts"--pigs that stay small. If your pig's weight stays the same even when on an appropriate diet there's a chance he's one.

However, you'll have to check with your vet on whether they'll neuter or not.