A guinea pig’s food routine should be built around constant access to good feeding hay, with appropriate fresh vegetables, a small measured portion of guinea pig pellets and clean water. The challenge is keeping that routine consistent and noticing when one animal is not eating normally.
Updated 24 September 2026: clarified portions and vitamin C, removed the routine mineral-block recommendation, and added a practical food-change and monitoring plan.
Eating less, fewer droppings or a change in drinking needs veterinary advice immediately. Do not use this feeding guide to diagnose weight loss, dental disease or a guinea pig that has stopped eating. See the RSPCA’s health guidance.
The everyday diet at a glance
| Food | Practical starting point |
|---|---|
| Good-quality feeding hay and suitable grass | Always available; this is the foundation of the diet. |
| Fresh vegetables and greens | A varied daily portion including a vitamin C source. |
| Plain guinea pig pellets | A small measured daily portion, not an endlessly refilled bowl. |
| Water | Clean drinking water available all the time; check delivery as well as quantity. |
| Fruit and sugary treats | Only small occasional extras; they do not replace the main foods. |
For healthy adult guinea pigs, PDSA gives one tablespoon of pellets and one cup of mixed fresh foods per animal per day as a starting point. Check the pellet manufacturer’s instructions and ask the vet about growing, pregnant, underweight or unwell animals. Do not turn approximate diet percentages into a reason to ration feeding hay.
Hay: keep it available and appealing
Timothy, meadow and orchard grass hays are commonly used feeding options. Choose fresh-smelling, clean hay and keep it dry. Discard damp, mouldy or heavily dusty material. A large bag is poor value if it spoils before you use it.
Offer feeding hay in more than one accessible place so both guinea pigs can eat comfortably. Some prefer a fresh pile; others use a suitable rack. Check racks for openings that could trap a head or foot. Keep the hay away from the wet toilet area and replace soiled material rather than simply covering it with another layer.
- Top up before the supply runs out, including for overnight grazing.
- Watch each guinea pig chew hay; a full rack does not prove either animal is eating it.
- Keep a note of the hay type and supplier when a change seems to affect intake.
- Do not replace rejected hay with a bowl of treats while waiting for a sick animal to improve.
Woodgreen’s feeding guide covers hay, safe forage and water choices. Suitable fresh grass adds variety, but never give lawnmower clippings. Offer only plants you can confidently identify from an uncontaminated source. If grazing outdoors, consider animal access and garden chemicals rather than assuming all garden grass is safe.
Vegetables, greens and vitamin C
Guinea pigs need vitamin C from their diet. Use a changing selection of safe fresh foods rather than relying on one favourite. The RSPCA lists bell peppers, cucumber, gem or romaine lettuce and suitable herbs among regular options; it puts foods such as kale, spinach, broccoli and carrot into smaller, less frequent portions.
Wash the food, remove spoiled parts and offer manageable pieces. Introduce unfamiliar items gradually. Remove uneaten fresh food before it spoils, and note which animal eats what. In a pair, an empty shared bowl can conceal a guinea pig that has eaten little.
Try a simple food diary rather than a rigid seven-day menu:
| Record | Why it helps |
|---|---|
| Foods and measured portions offered | Shows whether the diet is varied and prevents two carers giving the full allowance twice. |
| What each animal ate | Helps distinguish a preference from a broader loss of appetite. |
| New food introduced | Makes it easier to explain a recent change to your vet. |
| Droppings, water and weight concerns | Provides a useful history if you need veterinary advice; it is not a substitute for the call. |
Should I add vitamin drops or a mineral block?
A salt or mineral block is not a substitute for a balanced guinea pig diet or its vitamin C requirement. It should not be treated as an essential item on the everyday shopping list. Ask your vet about supplements if intake is uncertain or the animal has a medical need.
PDSA advises against vitamin C in drinking water because it degrades and the changed taste can discourage drinking. If supplementation is appropriate, follow the vet’s or guinea-pig-specific product instructions; do not guess a treatment dose from a general article.
Pellets: choose the right species and measure the portion
Use fresh, plain pellets formulated for guinea pigs, rather than rabbit food or a colourful muesli mix. Uniform pellets make selective feeding harder. Check the food label, best-before date and storage instructions when you buy.
Keep food cool and dry in its labelled packaging or a suitable labelled container. Mark when you opened it and avoid repeatedly pouring new food on top of an old supply. Vitamin C degrades in stored food, so buy quantities you can use while fresh.
Measure the daily allowance once. You can scatter it for foraging or divide it between feeding places, while checking each animal gets access. More pellets are not the automatic answer to weight loss: dental disease and other illness need assessment.
Foods to avoid and what to do after a mistake
Do not offer potato, onion, garlic, avocado, rhubarb, tomato leaves or vines, or unidentified wild plants. Keep chocolate, human snacks and other unsuitable foods out of reach. The RSPCA and PDSA food guides above provide fuller lists; their “avoid” lists include both poisonous foods and foods unsuitable for other reasons, which are not the same claim.
A shopping-list check is more useful than memorising a dramatic “toxic foods” graphic: identify the food, check a reliable species-specific source and leave it out if you are uncertain. If you suspect poisoning, contact the vet promptly with the food name, amount if known, packaging and time of exposure. Do not wait for symptoms or attempt a home remedy.
Water: check that the guinea pig can actually drink
Refresh water daily and check it at least morning and evening. Test the nozzle of a bottle, check its height and look for leaks. A bottle that stays full may be blocked; an empty one may have leaked. A suitable heavy bowl is another option, but keep it clean and stable.
In cold conditions, check for freezing. Never remove the only water source overnight. In warm weather, keep the drinking supply away from direct heat. Sudden changes in drinking or urination should be discussed with your vet.
A feeding routine the household can share
- Morning: observe both guinea pigs, replenish hay, refresh and test water, and measure the daily pellet and fresh-food portions.
- Later in the day: remove spoiled fresh food, check hay access and make sure the quieter animal has eaten.
- Evening: replenish feeding hay for the night, check water delivery again and review droppings and behaviour.
- When shopping: rotate appropriate fresh foods, check feed dates and review storage. Leave clear instructions before another carer takes over.
The routine should help you observe the animals, not promise that a fixed number of minutes is enough for every household.
Moving away from muesli without abrupt changes
If your guinea pigs are otherwise well, plan a gradual transition to suitable pellets while keeping hay and water constantly available. Change one part of the routine at a time so you can see what they accept. Mix a small amount of the new food into the existing food and build it up gradually as the old food is reduced.
Keep a short written plan so different carers do not switch at different speeds. Do not remove all familiar food to force an animal to accept a new product. PDSA describes a gradual change over two to four weeks; the appropriate pace depends on intake and the animal. If appetite drops, droppings change or the guinea pig seems unwell, stop treating it as a routine food switch and call the vet.
How to check whether the routine is working
Know each animal’s normal appetite, droppings, movement and weight trend. Weigh them regularly in a consistent way and record the results. Do not judge the diet from a glossy coat or assume that weight loss is just a feeding mistake.
Drooling, difficulty chewing, dropping food, a dirty bottom or reduced eating need veterinary attention. A shop conversation can help you compare food labels; it cannot identify the cause of illness or correct overgrown teeth. Bring the food record to the appointment if useful, but do not postpone care to complete it.
Questions about daily guinea pig food
Can I feed rabbit pellets instead?
Choose a guinea-pig-specific product with the appropriate nutrients, including vitamin C. If you run out or need an urgent substitute, ask your vet or supplier for suitable advice and keep hay and water available.
Does every guinea pig need the same amount?
No. General adult portions are starting points. Age, pregnancy, body condition and medical needs can change the plan. Ask your vet rather than increasing or restricting food sharply yourself.
What should I bring to the shop for feeding advice?
A photo of the food label, the measured portion and a list of hay and vegetables is useful. Tell us how many guinea pigs you have and whether all are eating normally. For illness or weight loss, contact your vet first.
Want To Feed Your Guinea Pig Properly? Come And See Me
Bring the food label and tell us what hay and fresh foods your guinea pigs currently eat. We can help you compare everyday supplies. For weight loss, reduced eating or a medical diet, speak to your vet first.