Your guinea pig’s main diet should consist of commercial timothy-based pellets made specifically for guinea pigs. These pellets contain added vitamin C, which is crucial to your guinea pig’s health. Guinea pigs cannot manufacture this vitamin on their own like most other mammals, so they must obtain all they need from their diet. Guinea pigs also need unlimited timothy hay and fresh, green vegetables each day.
Healthy treats for guinea pigs include carrots and fruit, such as berries, apples, pears and tomatoes. Give sweet treats only on occasion because they contain natural sugars that can cause diarrhea.
Guinea pigs also enjoy gnawing on dried, aged twigs from fruit trees. Be sure the tree was not sprayed with insect or fungicide before you offer this to your guinea pig. Make certain you dry and age the twigs before you feed them since fresh twigs can be poisonous.