Even though many people often state that rabbit manure can be applied directly to the garden, it contains a higher nitrogen content that most manures, which canburn the plants if applied heavily. So, like other natural "fertilizers" should be composted before adding to the garden. We generally till it in early in the year before we plant, giving it time to break down. You can also make a manure "tea", but the fecal pellets don't break apart easily so it is rather time consuming to try to mix it into a slurry.
Composting is also a very good reason due to health concerns (rabbit manure can harbor intestinal viruses that can infect humans).
Pam