Piggies can't make their own Vitamin C, so they need to get it from their diet every day. There are supplements such as vitamin treats, but the best source is fresh fruits and veggies.Some good foods to feed your pigs are apples, bananas, carrots kiwi, red and green pepers and cucumbers.
Your guinea pig's teeth grow, so you need to have untreated wood chews for your guinea pig to chew on. If your guinea pig is not interested in wood chews, you can get timothy or alfalfa hay cubes to keep their teeth from getting too long.
Guinea pigs need hay every day. Timothy hay is good for pigs, but alfala hay is best for pregnant or very young pigs. They also need a good quality guinea pig food. If the guinea pig food is old or was stored in a warm place or in direct sunlight the vitamin c in the food will lose it's potency.If you want to change your pig's food you need to mix it with the old food for a while so they get used to it.