How to Feed Rabbits and Guinea Pigs Properly

Hay is the diet, not the bedding

The biggest mistake people make with rabbits and guinea pigs is treating the bowl of colorful pellets as the meal and the hay as bedding or an afterthought. It is the other way round. Grass hay should make up the bulk of what these animals eat every day, and everything else is a supplement to it. Get that one thing right and you prevent most of the health problems that fill the exotic vet’s day.

Two reasons make hay non-negotiable, and both are built into how these animals are made. Their teeth grow continuously throughout life, and the only thing that keeps them worn down to a healthy length is hours of side-to-side chewing on tough, fibrous hay. A rabbit or guinea pig fed soft food instead grows overgrown, misaligned teeth that cut the mouth, stop it eating, and need repeated filing under anesthetic. The long chewing is not optional maintenance; it is how the mouth stays functional.

The second reason is the gut. These are hindgut fermenters whose digestive systems are built to keep a constant, high-fiber load moving through, and that movement depends on a steady intake of hay. Let the fiber drop and the gut slows or stops, a genuine emergency called gut stasis that can kill a rabbit within a day. Unlimited hay keeps the whole system moving in the way it is designed to, which is why it has to be available every hour of every day, not offered as a portion.

Choose the right hay and keep it coming

Not all hay is equal, and the type matters for adults. Grass hays such as timothy, orchard, or meadow are what you want for any rabbit or guinea pig past young growth: high in the tough fiber that wears teeth and drives the gut, and moderate in calcium and calories so it can be fed without limit. Keep a generous pile available at all times and refresh it often, because these animals graze constantly and will pick through and waste the flattened, dusty leftovers rather than eat them.

Quality shows when you handle it. Good hay is green, smells sweet and grassy, and is soft enough not to be all hard stalk, while poor hay is yellow, dusty, or musty and gets refused or, worse, causes respiratory irritation. In our rabbit and guinea pig hay reviews the most consistently fresh and leafy was Oxbow Western Timothy Hay, which arrives green and fragrant rather than the box of brown dust that cheap hay so often turns out to be.

Alfalfa is the exception worth knowing. It is a legume rather than a grass, far richer in calcium and protein, which suits young, growing animals and nursing mothers but is too rich for healthy adults, in whom it feeds obesity and bladder stones. Feed grass hay to adults and save alfalfa for the babies. And skip the pretty packs of dried fruit, seeds, and colorful bits sold as treats, which are mostly sugar and starch these animals are not built to process.

Fresh greens and a careful hand with pellets

After hay, a daily portion of fresh leafy greens does most of the rest of the job, adding moisture, variety, and a range of nutrients. For guinea pigs greens carry a special weight, because they cannot make their own vitamin C and go downhill without a daily source, so vegetables such as bell pepper, leafy greens, and a little parsley are not a luxury but a requirement. Rabbits benefit from greens too, chiefly leafy vegetables and herbs rather than watery salad.

Introduce any new green slowly and watch what happens. A sudden pile of unfamiliar vegetables can upset a delicate gut and cause soft stools, so add one new item at a time in small amounts and build up over days. Wash everything, avoid the well-known dangers such as anything from the onion family, and go easy on high-calcium greens for rabbits prone to bladder sludge. A varied handful of appropriate greens a day, rather than one big load, keeps the gut settled.

Pellets are the smallest part of the diet and the one most people overdo. A measured spoonful of a plain, high-fiber grass-based pellet each day tops up vitamins and minerals, but pellets are calorie-dense and too moreish, so a bowl left constantly full leads to a fat animal that fills up on pellets and stops eating the hay its teeth and gut depend on. Ration pellets to a small daily amount, choose a uniform grass-based type rather than a muesli mix the animal can pick sugary bits out of, and let hay stay the star.

Water, and how you present the food

Fresh water has to be available at all times, and how you offer it affects how much they drink. Some rabbits and guinea pigs prefer a heavy ceramic bowl, which lets them drink in a natural posture and take a proper amount, while others do better with a bottle that stays clean and cannot be tipped or fouled. Whichever you use, check it works every single day: a stuck bottle valve or a bowl knocked over means an animal going without water, which is dangerous fast, especially for a guinea pig.

Where the food sits in the enclosure matters more than it seems. Piling hay in a corner where the animal also toilets gets it soiled and refused, so many keepers use a rack or feeder that keeps the bulk of the hay clean and off the floor while still letting the animal pull it out to graze. A common and clever trick is to site the hay near the litter area, since these animals like to eat and toilet at the same time, which encourages both grazing and good litter habits at once.

The enclosure itself needs to be big enough to hold all this alongside room to move, because a cramped hutch leaves no space for a proper hay pile, a water source, a litter spot, and exercise. In our small animal cage reviews the roomiest and best-built was the MidWest Critter Nation, whose wide, deep shelves give space for a generous hay station and separate feeding and toilet areas without crowding the animal out of somewhere to stretch and run.

Reading the signs that the diet is off

The reward for getting the diet right is an animal that eats steadily, passes plenty of firm droppings, and keeps its teeth and weight in good order, and those same signs are your early warning when something slips. Droppings are the clearest gauge: lots of round, firm pellets mean a gut doing its job, while a sudden drop in the number or size of droppings, or none at all, is a red flag for the gut slowing down. A rabbit that stops eating and stops passing droppings is a same-day emergency, not a wait-and-see.

Watch the mouth and the weight too. Drooling, dropping food, a wet chin, or losing condition despite a full bowl can all point to overgrown or misaligned teeth that need a vet’s attention, and these creep up slowly on a diet too low in hay. Guinea pigs going quiet, hunched, or off their food may be short of vitamin C or brewing something that needs looking at promptly, since prey animals hide illness until it is advanced.

None of this is a substitute for a vet who knows small mammals, and that is worth lining up before you need one, because not every practice is confident with rabbits and guinea pigs. We test the gear and lay out the feeding basics rather than treat the animals, so an animal that stops eating, stops passing droppings, is drooling, or has gone suddenly quiet needs an exotic-savvy vet quickly. Feed hay first, greens daily, pellets sparingly, and water always, and you will be at that vet far less often.