While overeating is a concern, guinea pigs need to eat constantly to keep the beneficial flora in their gut happy and active.

How Much Watermelon Can Guinea Pigs Eat? Guinea pigs can eat one small slice of watermelon up to a few times a week if it’s the only fruit in their diet that week. You’ll want to limit other ...

These animal were euthanized. The animals were housed on pine-chip bedding, fed a commercial guinea pig diet, and given fresh leafy vegetables and lucerne (alfalfa) hay to supplement their diet.