My rabbits produce a lot of manure. Most of the time, I spread it over the woods and let it compost. The poison ivy gets extra green, but the manure isn't going to any real use.
Rabbit manure is probably the best fertilizer you can get for your garden. It's natural, easy, and cheap. Bunny berries can be spread directly on a garden without composting, making it a very quick and easy fertilizer fix. This site describes the stuff pretty well: