Timothy Hay – Offer as much as your pet can eat (free choice). Orchard grass, oat hay, or meadow grass can be offered as alternatives for pickier animals. Avoid alfalfa and other hays high in calcium in animals over 6 months, as these may predispose to development of urinary bladder stones.
Pellets – While not strictly necessary, pellets may be offered to supplement the diet of hay. Use a timothy hay-based pellet, such as Cavy Cuisine by Oxbow (oxbowhay.com) or Supreme Selective brand pellets. Avoid pellets mixed with seeds, as many pigs eat the high fat seeds and leave the pellets. Offer no more than about 1/8-1/4 cup pellets total daily.
Fresh greens – Can be offered daily. Good choices include the following: romaine lettuce, red/green leaf lettuce, escarole, watercress, clover, Swiss chard, bok choy, endive, and turnip tops. Avoid dandelion, collard greens, turnip greens, mustard greens, kale, and broccoli due to their high calcium content, which may predispose to development of bladder stones. A good rule of thumb is that darker greens tend to have higher calcium levels and should be avoided. Small pieces of carrot, bell pepper and other high vitamin C foods can be offered as occasional treats in small amounts. We do not recommend supplementing vitamin C in the diet solely though vegetables (i.e. large amount of bell peppers) as it does not provide enough and in large amounts, may cause GI upset.
Vitamin C Supplement – This is a necessary part of every guinea pig’s diet as they require approximately 50 mg of vitamin C daily, which often cannot be provided through diet alone. This can be satisfied by giving a liquid oral Vitamin C supplement or a high quality chewable supplement. Do not add the vitamin C to the water, as this promotes bacterial growth and is not a consistent way to dose your pig. Vitamin C also breaks down quickly when exposed to light. Vegetables high in Vitamin C, such as red, orange and green bell peppers, can be offered as an additional source of Vitamin C, but are not recommended as the sole source.