Donkeys eat dry matter and fibrous foods such as straw, hay, bark and shrubs. Although they eat grass, they should not overfeed on either it or clover.
In the wild, a donkey feeds on a variety of vegetation, from bark and shrubs to berries and grass. In captivity, a donkey requires high-fiber foods, such as barley and hay, with only small amounts of low-fiber grasses. Chaff or grain husks and fiber nuts are two other high-fiber options. Owners need to avoid feeding a donkey oats, as this grain can cause inflammation of the hooves or laminitis. A donkey also requires a salt or mineral lick.
Barley straw is the main component of a donkey's diet. Not only does it have high fiber, but it is low in calories, which keeps the animal from putting on too much weight. An owner should only feed a donkey oat, wheat or linseed straw under certain circumstances. Oat straw has a higher calorie content and is only suitable for older donkeys, while wheat straw requires a young donkey with strong teeth to eat it. Linseed straw can only be fed to a donkey if the linseed has been previously boiled.
An owner needs to allow hay to dry out for at least three months before feeding it to a donkey, and only give it to the donkey if it contains no mold. Both meadow hay and seed hay are good options because of the high fiber content, but cow-pasture hay should only be fed to a donkey if its is mixed with straw. When procuring meadow hay, an owner needs to make sure that there is no ragwort in it, a yellow wildflower that is toxic to donkeys.