Guinea pigs don’t require a lot of complicated care, but feeding them right is essential for the health of these friendly pets. Guinea pigs are vegetarians who fare well on a diet of pellets, hay, vegetables rich in vitamin C and limited fruits. Feed a combination of these foods regularly to ensure adequate intake of necessary nutrients. Also always provide your guinea pigs constant access to clean, fresh water.
Guinea pigs are unable to make their own vitamin C, so feed a balanced commercial pelleted guinea-pig-specific diet supplemented with vitamin C. Place the pellets in a heavy crock or a pellet dispenser that hangs on the side of his cage. Some signs of vitamin C deficiency in a guinea pig include weight loss, scurvy, lethargy, bleeding gums and lameness. Feed between an eighth of a cup and a quarter-cup of pellets per day.** Replace uneaten pellets daily, as stale pellets tend to lose vitamin C quickly.
Free Choice Hay
Give your guinea pig as much hay as he wants every day. It’s good for his teeth to chew on it, and the roughage aids his digestion. Grass hay, such as orchard or timothy hay, is the best choice for a guinea pig. Alfalfa will work in a pinch, but it contains too many calories for guinea pigs to eat on a regular basis and will cause your pet to gain too much weight. It also has too much calcium, which can lead to bladder stones. Hang a hay rack from the side of your guinea pig’s cage to keep his hay clean and fit to eat.
A Variety of Vegetables
Guinea pigs love treats, and for them almost any kind of vegetable counts as a tasty treat. The Metropolitan Guinea Pig Rescue recommends giving cavies several different vegetables each day, in small amounts. Offer him a few leaves or a small slice of washed, unpeeled veggies high in vitamin C every day. Try basil, beet greens, bok choy, cilantro, clover, collard greens, broccoli, green peppers, mint, mustard greens, peppermint leaves, radish tops, romaine lettuce, raspberry leaves and wheat grass. Place it in a clean crock or other dish he can't chew or tip over. Discard anything he doesn’t eat by the next day. Introduce each new vegetable slowly and make sure that your pet doesn’t react poorly to it before you make it a regular part of his diet.
A guinea pig will happily munch on almost any fruit to the exclusion of all else, but that sort of diet isn’t good for him. Limit your cavy's fruit to a piece about an inch square, placed in a crock or other clean container. Offer him fruit once or twice per week. It’s okay to leave the peel in place when you give it to him, but be sure to discard anything he doesn’t finish by the next day.
Be careful when offering sweet, sugary fruits such as bananas and grapes, as they can make a cavy gain too much weight -- but he can have them sometimes. Other fruits to offer are apples, papaya, pineapple, peaches, pears, blueberries, strawberries, raspberries, tomatoes and melons. Always introduce new foods carefully to make sure your guinea pig doesn’t get sick from the change.
Never Feed Some Foods
Some foods can kill a guinea pig or lead to a serious illness -- never give your pet human treats. Avoid chocolate, bread, crackers, pasta, yogurt drops, cereals, dairy products or candy. These and other foods can cause overgrowth of intestinal bacteria, potentially fatally. He’ll be just as happy, and healthier, with fruits and vegetables as his only treats. Make sure your cavy never eats food that is moldy or otherwise appears spoiled.