If you decide to give your bunnies oatmeal, be sure to buy the old fashioned oatmeal, do not buy the Quick Oats.
Oatmeals - Regular or rolled oats are groats that have been steamed and made into flakes. The "rolling" of them flattens them into the flakes. Sometimes you'll see steel cut oats advertised. Steel cut oats are created when a metal blade cuts them into 2 or 3 pieces.