I grow wheat grass for Honey. You can get a pound bag of wheat berries at some groceries, at a health food store, or online. Yes, it's in a windowsill tray this time of year. Grow it just like grass ie plant thickly & just cover the wheat berries with enough soil you can't see them anymore. When it's about 4" tall you can cut off 3" & give it to your rabbit. Replant when the wheat grass stops regrowing. Honey really likes it in her diet.