Have you tried cilantro? Most bunnies love that. Dandelion greens are also a favorite, but you can usually only find them in natural foods stores. If you garden at all, you can find dandelion seeds at a couple of places online – Burpee Seed Co. and Johnny’s Seeds. Johnny’s has more varieties. They have the Italian kind and the chickory seeds. You can gather them from your yard, just make sure that they haven’t been sprayed with anything.
Carrot tops are usually a favorite, but they can be hard to find – at least, the good fresh ones. Some stores will have carrots with tops but the tops are old and wilted. I get mine from a natural foods store, either Fresh Market or Earth Fare. You can even get a carrot bunch with tops that aren’t so fresh, then resprout your own fresh tops. Cut the carrot so that there is about an inch of the carrot at the top, with about an inch of greens attached, and stick the carrot part in some soil or in water. It will resprout. You can use containers if you don’t have a garden.
Some people say to get a rabbit to eat something, to brush it against their nose/mouth area. Sometimes they will grab it and start eating.