Some people do feed their rabbit the occasional Cheerio and they say it’s fine, but the experts agree that rabbits shouldn’t eat any processed grain products, or “human” foods, like Cheerios. (See sources below)In the wild, rabbits eat occasional grains, but only in their whole form: when grains are processed, they lose their nutritional value (bran) and their sugars and starches are increased (which is very unhealthy for rabbits). Rabbits get all the grain nutrients they need from their specially-formulated pellets: they don’t need any more as treats.If you want to give your rabbit a treat, stick to whole, natural, fresh foods, because fresh vitamins and nutrients are what pellets are missing: e.g. fruits or vegetables (like squash, carrots, berries, apple). You can also offer an occasional oat groat or wheat berry: this is the grain in its whole form – this is NOT the same as oatmeal, rolled oats, bread, crackers, etc.
Treats must be limited in a rabbit’s diet, so if you offer things like Cheerios, which have no nutritional value for rabbits, then you’re missing out on the opportunity to offer foods with good nutrients and vitamins. Too many sugars, starches, carbohydrates etc in a rabbit’s diet leads to illness (like gas, GI stasis, obesity, etc). Make sure you’re feeding your rabbit a balanced diet of hay (as the majority of the diet, in unlimited amounts), and pellets and fresh veggies daily (dark greens like kale are ideal). The House Rabbit Society recommends no more than 2 tablespoons of fresh treat foods per day for a healthy, normal 6 pound rabbit.