Forage feeding? How to increase activity?

Hello everyone!

Susu had a vet appointment yesterday. The good news is that all tests came out pretty good and there's no immediate health concerns. However, the vet is concerned about her weight. In her words, Susu is obese. I know it's rare for chinchillas to overeat, but the vet was concerned that she could feel fat deposits and recommended Susu loses some weight. This isn't the first time I had heard that but it had been hard to limit her access to pellets while she had a cagemate...

Forage feeding? How to increase activity?