Small Pet Nutrition: Feeding Rabbits, Guinea Pigs, and
Proper nutrition is the single most important factor in small pet health. More than any other aspect of care, what you feed your small pet determines their lifespan, disease risk, and quality of life. Yet dietary mistakes are the most common cause of illness in rabbits, guinea pigs, hamsters, rats, and ferrets. Many commercial pet foods are formulated based on production cost rather than nutritional science, and well-meaning owners often overfeed treats or choose the wrong staple foods.
Small pet nutrition is not one-size-fits-all. Rabbits and guinea pigs are herbivores with digestive systems designed for high-fiber plant matter. Hamsters are omnivores adapted to a diet of seeds, grains, and insects. Rats are opportunistic omnivores with flexible nutritional needs. Ferrets are obligate carnivores requiring a meat-based diet. Feeding all these species the same food, as some commercial brands suggest, causes serious health problems. This guide covers both universal nutritional principles and species-specific requirements.
The Hay Foundation
For rabbits, guinea pigs, chinchillas, and other herbivorous small pets, hay is the foundation of the diet. It provides the insoluble fiber that keeps the digestive system moving properly and wears down continuously growing teeth.
Why Hay Matters
The digestive systems of herbivorous small mammals evolved to process large quantities of fibrous plant material. Hay provides the bulk necessary for proper gut motility. Without adequate hay, the digestive tract slows down, leading to gastrointestinal stasis — a potentially fatal condition in which food stops moving through the gut. According to veterinary studies, gastrointestinal stasis is one of the most common reasons rabbits are brought to emergency clinics.
Hay also maintains dental health. Rabbit and guinea pig teeth grow continuously throughout their lives, at a rate of up to five inches per year. Chewing hay grinds the teeth down at the same rate, preventing overgrowth. Dental disease affects up to 60 percent of pet rabbits that are fed inadequate hay diets, according to research published in the Journal of Veterinary Dentistry.
Types of Hay
Timothy hay is the best all-purpose hay for adult rabbits and guinea pigs. It has an ideal calcium-to-phosphorus ratio and moderate protein content. Orchard grass hay is a good alternative with similar nutritional content and a softer texture that some animals prefer. Meadow hay contains a mix of grasses and is nutritionally similar to timothy.
Oat hay is higher in fiber and lower in protein than timothy. It is a good option for overweight animals. Wheat hay and barley hay are similar to oat hay. Alfalfa hay is too high in calcium and protein for adult herbivores but is appropriate for young, growing animals under six months of age and for pregnant or nursing females.
Offer a variety of hays to encourage eating. Some small pets are picky about hay, and switching between types maintains interest. Replace hay daily — animals will not eat hay that has become soiled, damp, or stale.
How Much Hay
Herbivorous small pets should have unlimited access to hay at all times. The hay rack or feeder should never be empty. An adult rabbit typically consumes a pile of hay the size of its own body every day. Guinea pigs eat slightly less but still need constant access. Hay should make up approximately 80 percent of the total diet for rabbits and guinea pigs.
Pelleted Foods
Pellets provide concentrated nutrition but should be fed in controlled portions. They are supplements to the hay-based diet, not replacements.
Choosing Pellets
Select plain, uniform pellets without seeds, nuts, dried fruit, or colored pieces. These additions are high in sugar and fat and encourage selective feeding, where the animal eats the treats and leaves the nutritious pellets. High-quality pellets have a high fiber content — at least 22 percent fiber for rabbits and 18 percent for guinea pigs.
Check the expiration date on pellets. Vitamin C in guinea pig pellets degrades within 90 days of manufacture. Pellets stored in warm or bright conditions lose nutritional value faster. Store pellets in a cool, dark, dry place and buy only what you will use within three months.
Portion Control
Most small pets need surprisingly few pellets. Adult rabbits need about one-eighth to one-quarter cup of pellets per five pounds of body weight daily. Guinea pigs need about one-eighth cup per day. Hamsters need about one tablespoon for Syrians and one teaspoon for dwarfs. Rats need about 15 to 20 grams daily. Overfeeding pellets causes obesity, which is a major health problem in pet rabbits and guinea pigs.
For species-specific feeding amounts, see our guides for rabbits, guinea pigs, and other small pets.
Fresh Vegetables and Fruits
Fresh produce adds moisture, vitamins, and variety to the diet. The specific needs vary by species.
Herbivore Vegetables
Rabbits and guinea pigs need daily fresh vegetables. Dark leafy greens should form the bulk of the fresh food portion. Safe daily options include romaine lettuce, red leaf lettuce, green leaf lettuce, cilantro, parsley, basil, mint, and dandelion greens. Arugula, endive, escarole, and radicchio add variety.
Other safe vegetables include bell peppers, zucchini, cucumber, broccoli (leaves and stems), celery, and carrots (in limited quantities due to sugar). Introduce new vegetables one at a time and monitor for digestive upset. Feed about one cup of vegetables per two pounds of body weight for rabbits and about one cup per guinea pig daily.
Fruits should be treats fed in small quantities — a one-inch cube of apple or a single strawberry once or twice daily. The sugar content in fruit can disrupt the gut microbiome if fed in excess.
Omnivore Fresh Foods
Rats and hamsters benefit from small amounts of fresh vegetables and fruits. Safe options include broccoli, carrot, cucumber, bell pepper, apple, banana, and berries. Offer a piece about the size of the animal’s thumb once daily. Remove uneaten fresh food after a few hours.
Rats also need occasional protein from cooked meat, eggs, or mealworms. Hamsters benefit from small amounts of protein as well. These additions should not exceed 10 percent of the total diet.
Foods to Avoid
Several foods are toxic to small pets and must never be fed. These include chocolate, caffeine, alcohol, avocado, onion, garlic, chives, leeks, rhubarb, raw potato, green tomato, and fruit pits or seeds (apple seeds contain cyanide). Iceberg lettuce has minimal nutritional value and can cause diarrhea. Dried corn and sunflower seeds are high in fat and should be limited.
Water
Clean, fresh water must be available at all times. Water bottles with metal sipper tubes are common for small pets, but heavy ceramic bowls are often preferred because they allow more natural drinking posture. Whichever method you choose, check it twice daily and clean it weekly.
Water bottles can develop algae or bacterial growth, especially in warm conditions. Replace the water daily and clean the bottle with a small brush and mild soap. Check that the sipper tube is not clogged or leaking, which can wet the bedding and cause respiratory problems.
Species-Specific Diets
Rabbits
80 percent hay, 10 percent fresh vegetables, 5 percent pellets, 5 percent treats. Timothy hay unlimited, alfalfa hay only for young rabbits. Avoid muesli-style mixes, which cause selective feeding and dental disease. The Rabbit Welfare Association recommends a minimum of 22 percent fiber in pellets.
Guinea Pigs
80 percent timothy hay, 10 percent fresh vegetables high in vitamin C, 5 percent pellets, 5 percent treats. Vitamin C is essential — red bell pepper, kale, and parsley are excellent sources. Guinea pigs need 10 to 30 mg of vitamin C per kilogram of body weight daily.
Hamsters
High-quality lab block or pellet base, supplemented with small amounts of vegetables, fruits, and protein. Avoid sugary treats and seed mixes with high fat content. Syrian hamsters need about one tablespoon of pellets daily.
Rats
Lab blocks as the dietary foundation (15 to 20 grams daily for adults), supplemented with vegetables, fruits, and protein. Rats need a varied diet with fat content of 5 to 10 percent. Avoid high-fat seed mixes.
Ferrets
High-protein, high-fat, low-carbohydrate diet. Commercial ferret food or a properly formulated raw diet. Ferrets should never be fed hamsters or rabbit food, which is too high in carbohydrates. For more on ferret nutrition, see our ferret care guide.
Treats and Supplements
Treats should make up no more than 5 percent of the daily diet. Commercial treats sold in pet stores are often high in sugar, fat, and artificial colors. Healthier alternatives include small pieces of fresh fruit, herbs, hay-based treats, and freeze-dried vegetables.
Vitamin supplements are generally unnecessary if the diet is varied and nutritionally complete. The exception is vitamin C for guinea pigs, which must be supplemented through fresh vegetables or fortified pellets. Calcium supplements should not be given without veterinary guidance, as excess calcium causes bladder stones in rabbits and guinea pigs.
Probiotics can be beneficial during or after antibiotic treatment, but choose products specifically formulated for small pets. Human probiotics may contain strains that are not beneficial or are harmful to small animals.
FAQ
How much hay should my rabbit eat daily?
Rabbits should eat a pile of hay roughly the size of their own body every day. Hay should be available 24/7 and should make up approximately 80 percent of the total diet.
Do guinea pigs need vitamin C supplements?
Guinea pigs cannot produce their own vitamin C and need 10 to 30 mg per kilogram of body weight daily. Fresh vegetables high in vitamin C, like red bell pepper and kale, are the best source. Supplementation is recommended during illness or pregnancy.
Can hamsters eat fruits and vegetables?
Yes, but in very small amounts — a piece about the size of the hamster’s ear once daily. Safe options include apple, banana, carrot, and cucumber. Remove uneaten fresh food after a few hours.
What foods are toxic to small pets?
Chocolate, caffeine, alcohol, avocado, onion, garlic, rhubarb, raw potato, and fruit pits are toxic to most small pets. Iceberg lettuce should be avoided due to minimal nutritional value.
How often should I feed my ferret?
Ferrets have fast metabolisms and need small meals throughout the day. Feed two to three meals daily or provide continuous access to high-quality ferret kibble. Fresh water must always be available. See our small pet health guide for more dietary and health information.