Most rodent and lagomorph species do well on diets based on commercial laboratory rodent pellets or rabbit pellets. Rabbits, hares, pikas, marmots, and prairie dogs can be maintained on rabbit pellets, alfalfa or grass hay, and a limited amount of assorted vegetables. Most other sciurids can be fed rat pellets and a limited mixture of sunflower seeds, millet, corn, and rolled oats. Ground squirrels can also be offered a limited amount of green leafy vegetables, carrot, and apple. Most murids, cricetids, gophers, dormice, and jerboas do well on rat pellets; for smaller species, mouse pellets, a seed and grain mix, green leafy vegetables, carrot, and apple can be fed.
Hay should be made available to voles and lemmings. Captive voles may be difficult to manage unless a high-fiber rabbit pellet is used. Muskrats, agoutis, and capybaras will eat a combination of rat and rabbit pellets along with alfalfa hay, carrot, and apple. Porcupines can be fed rat pellets, rabbit pellets, and dry dog food in equal portions along with some apple, carrot, and bread; evergreen (willow) branches should be made available whenever possible. It is also advised to provide bones for gnawing. Beavers will eat a combination of rabbit pellets, large herbivore pellets, and dry dog food, regularly augmented with willow, poplar, aspen, or alder branches. Feeding a high amount of alfalfa and pellets containing high amounts of calcium is not advised because it can lead to urolithiasis in some rodent and lagomorph species.
Guinea pigs should be offered commercial guinea-pig pellets instead of a rabbit pellet with vitamin C added, along with greens and carrots. Many guinea-pig pellets have lower amounts of fiber due to urolithiasis Capybaras have reportedly developed gum disease and signs of scurvy when vitamin C is lacking. Also, guinea pigs are known to require a dietary source of vitamin C; other lagomorphs and rodents may benefit from it.