Guinea pigs are, of course, herbivores. They are little veggie eating machines. But if you are going to be a responsible owner, you need to know what they can eat, what they like to eat, and what cannot eat. First, remember that guinea pigs, like humans, do not make their own Vitamin C. If a pig does not get adequate Vitamin C in her diet, she will get sick and can even die. So when choosing a brand of pellets, make sure the bag says that it’s for guinea pigs (not rabbits or gerbils) and make sure it states that it contains Vitamin C.
The mainstay of their diet is Timothy hay. I cannot state enough how important it is to provide an unlimited supply of Timothy hay. The hay aids in your pigs’ digestive system and help them grind their teeth down. People often make the mistake of buying Alfalfa hay. This is a big no-no. The amount of calcium in Alfalfa hay is too much for guinea pigs and can cause bladder stones. So, give them Timothy hay and only Timothy hay. Make sure they get fresh hay every day as well. If hay has been sitting there for awhile, it dries out and they often will not eat it. Also, they often use the hay as a bathroom area, and once it gets soaked in urine, it is no longer appealing. Pigs can be picky that way.
They need daily vegetables. My piggies love romaine lettuce and carrots. But again, you should be conscious of giving them foods that is heavy in Vitamin C, because even though the pellets contain the vitamin, it is impossible to know how old the pellets are, and as Vitamin C break down over time, older pellets will lose their Vitamin C potency. So try to find some veggies rich in Vitamin C that they will eat. This may be a harder trick than it sounds, because I’ve found that once a guinea pig gets in her head what she will or will not eat, it’s difficult to change her mind. Also, they might love something one day, and then the next day, won’t touch it. They are like people in this capacity. We get tired of the same old thing too, you know. Vitamin C rich vegetables include kale, parsley, mustard leaves, spinach, all of which, none of my pigs will eat. This is not to say your pigs won’t love these, but mine are a bit on the difficult side. They will, however, eat bell peppers, and this has a good amount of C.
If all of your efforts have been thwarted and you’re concerned that your pet is not getting enough Vitamin C, look into giving them Vitamin C supplements. I do not recommend the drops that can be added to the water. First, this can make the water taste funny to the pigs and they won’t drink it. Second, the light exposure will break down the Vitamin C, so it’s really just pointless. My veterinarian recommended a chewable Vitamin C tablet, although for it to work, you have to first convince your pig to eat it. Of course, none of mine would touch it. But if all else fails and you are convinced your guinea pig is not getting adequate Vitamin C, you can give them the liquid drops via syringe.
To recap, your piggies must have pellets which state they are for guinea pigs and have Vitamin C. They also must have an unlimited supply of Timothy Hay and daily fresh vegetables. And don’t forget they need fresh water too! Please note, I am an experienced and knowledgeable guinea pig owner, but I am not a medical professional. Always consult for veterinarian for any health concerns.