Guinea pigs are natural herbivores and would spend their time foraging and grazing in small herds in the wild. They need to be fed the types of food they have adapted to eat. Their teeth are continuously growing, which is one of the reasons why they need plenty of roughage to chew; this wears down their teeth and helps prevent serious dental problems. Providing sufficient fibre in their diet is also very important for both their gastrointestinal system and general health.
For your guinea pigs to be happy and healthy, you should:
- Ensure that your guinea pigs have a constant supply of grass and/or grass hay (such as Timothy, Oaten, Barley, or grassy hay). Guinea pigs should not be fed Lucerne (alfalfa) or Clover hay, as these are too high in protein and calcium. The hay that you feed should be available 24 hours a day and of good quality; dry, sweet smelling, and not contain any mold, mildew or fungus.This is paramount in providing a complete diet and encourages the guinea pigs to chew for long periods of time. This chewing helps to wear down their continuously growing teeth and is very important in maintaining dental and gastrointestinal health. The hay should ideally be contained in a hayrack or basket to prevent it sitting on the enclosure floor and getting contaminated by your guinea pigs’ waste and becoming damp, dirty, and mouldy; this is unhygienic and could make your guinea pigs sick.
- Offer a variety of fresh leafy green vegetables & herbs daily. Some examples of these include dark leafed lettuce varieties such as rocket, dandelion greens, snow peas, and herbs such as marjoram, borage, marigold, nasturtium, rosemary, parsley, coriander, basil, and dill. Other foods that are good to fed guinea pigs a few times a week include broccoli, cabbage, endive, carrot tops, Brussels sprouts, kale, silver beet, mint, and fruits such as apples (but with no seeds), mango, and papaya.
- Provide your guinea pigs with a dietary source of Vitamin C because (like humans), guinea pigs cannot synthesise Vitamin C from other food substances. Vitamin C rich foods such as leafy green veggies and capsicums (green, orange, and red) should be fed to your guinea pigs daily. Foods like carrots, kiwifruit, berries, and pineapple are also great as a source of Vitamin C and a tasty treat for your guinea pigs but only feed them a few times a week, not every day, as these foods have quite a high sugar content.
- Make sure that you source grass, herbs, fruits, and vegetables that have not been sprayed by any chemicals, as these could harm your guinea pigs. Lawnmower clippings should never be fed to your guinea pigs as these can cause gastrointestinal blockages and make your guinea pigs very sick.
- High quality commercial ‘Guinea Pig’ pellets (minimum 16% fibre content) may be offered in small quantities, but these should not form the main part of the diet. Although many contain adequate levels of Vitamin C when fresh, this is only when the food is very fresh and within just a few months these foods no longer contain Vitamin C.
- Uneaten food should be removed from your guinea pig’s enclosure after a few hours to ensure that these don’t rot or become mouldy and harm your guinea pig.
- Please remember that any new foods should be introduced gradually to allow your guinea pigs’ digestive system to adjust, so they don’t get sick. Mix any new food into the existing diet in small quantities, slowly increasing the amount over two weeks.
- It is important to also know what not to feed guinea pigs, as there are plenty of items that might seem harmless but can in fact cause significant health issues. Make sure you do not feed your guinea pigs the following foods (this is not an exhaustive list): cereals; grains; nuts; seeds; dried beans, corn, and peas; buttercups; garden shrubs (such as hemlock or privet); lilies of any kind; sweet peas; nightshade; oak; avocado; onion grass; onions; potato tops; mushrooms; daffodils; foxglove; rhubarb leaves; and human foods such as breads, biscuits, sweets, sugar, breakfast cereals, dairy products, chocolate, pasta, crackers, or pickled foods.
- If you need to change your guinea pig’s diet, please make sure you introduce any changes gradually over a few weeks.
- Provide clean fresh water at all times. Multiple water dispensers should be available and enclosures should be fitted with a water bottle and a small water bowl should be available as well.
Providing the opportunity for your guinea pig to graze on grass is also important to their wellbeing. If they do not have an areas where they can graze safely (for example, free roaming in a safe enclosure), then offering cut grass is another alternative (however, they should not be fed lawn trimmings, as these can cause digestive upsets). When you harvest grass to feed to your guinea pigs you need to make sure it is safe. Ensure that the grass has NOT been sprayed with any herbicides or pesticides, don’t harvest grass from the roadside as it may be contaminated with exhaust fume toxins or from areas where it might have been soiled by other animals (e.g. livestock or dogs), the grass should be fresh and green and not have any mould, mildew or fungus on it. Just as with hay, Lucerne (alfalfa) should not be given fresh and clover should be avoided where possible and not given in large quantities).
It is important that guinea pigs are introduced to a variety of different and healthy foods from a young age, as they may not try or accept new foods later in life.
Please note that it is normal for guinea pigs to eat their soft, nitrogen-rich faeces that are derived from their caecum after they pass them (coprophagy). This does not indicate any kind of dietary deficiency or abnormality and guinea pigs should be allowed to do this.