As herbivores, a prairie dogs diet is made up of grass hays. They should always have a good amount of it at their disposal and any left over hay should be replaced everyday in order to make sure you are feeding them fresh hay. Make sure to keep the hay you are feeding them in a dry place to avoid molding. Note that prairie dogs should never be fed alfalfa hay. Timothy hay pellets can be used as a treat for prairie dogs and should be given along with grass hay. Hiding the treats within the hay can encourage natural foraging instincts.