When feeding your rabbit or guinea pig, remember their GI tract is similar to a horse. Fresh grass hay such as timothy or orchard grass should be their primary food. Pelleted food is similar to what is fed to a horse and only small amounts are healthy: ¼ cup per day for a guinea pig and ¼ cup per day for 3-5 lb rabbit, unless they are under 9 months and still growing. For rabbits, feed at least 1 cup fresh greens such as cilantro, carrot tops, parsley, or romaine lettuce per day. For guinea pigs, feed ¼ cup of greens such as kale leaves and green pepper per day. Guinea pigs need 50mg of Vitamin C per day in the form of kale and green pepper or a one a day Vit C from Oxbow at oxbowanimalhealth.com