It's normal for your guinea pig to put on weight but it's not necessarily healthy. Guinea pigs are prone to put on too much weight because they're greedy.
Here are a few tips to help you maintain your guinea pig's weight at a healthy level and take care of her welfare more widely:
How to make sure your guinea pig is healthy1. Weigh your guinea pig every week on kitchen scales and make a note of the weight. This record could be very useful to your vet and will help you track things accurately.
2. Feed your guinea pig the best and most nutritious food you can afford.
3. To help your guinea pig stay active, scatter their food around their play area and toys to encourage them to move about a bit more.
4. Remember that with a female guinea pig, one thing that will make her put on weight is pregnancy. Keep her away from boy guinea pigs unless you want a litter of mini guinea pigs.