Rabbit manure, or pellets, is a high-quality soil conditioner, according to the New Mexico State University Extension program. Rabbit pellets are less likely to burn plants than other manures, and in the case of pet rabbits who have been fed rabbit feed, their manure is unlikely to contain inconvenient weed seeds. Get maximum benefit from your rabbit pellets by composting them using red wiggler worms underneath your rabbit cages before adding them to your garden as mulch or a soil amendment.
Stand three 1-inch by 6-inch boards on their sides on the ground around the outside of your rabbit hutch. Place a used brick at each end of each board to hold it upright, creating a three-sided box 6 inches high.
Remove rabbit manure and bedding from the rabbit hutch and rake it into the three sided box under the hutch with a leaf rake. Place the fourth board on the fourth side, closing the box, and hold it in place with two remaining used bricks.
Add red wiggler worms to the rabbit manure under the hutch. Use about 200 red wigglers for an average 4 foot by 8 foot hutch containing two rabbits; adjust the number of worms if you have more or fewer rabbits.
Add more rabbit manure and bedding to the box under the hutch each time you clean out the cage for one month. Water the rabbit manure until it is damp, but not saturated, if temperatures are quite hot or the weather is very dry.
After one month, rake the composting rabbit manure under the hutch towards one end of the box, preferably the end away from the area of the hutch which your rabbits usually use for litter purposes. Continue adding fresh rabbit manure and bedding to the cleared end of the hutch.
Remove the board at the end where the oldest composting rabbit manure is located when the rabbit manure appears to be well-decomposed, resembling rich earth. Shovel the composted manure into a wheelbarrow using a manure shovel. Replace the removed board, and rake the remaining rabbit manure down to the area you have just cleared.
Remove some of the red wigglers from the wheelbarrow with your hands and return them to the remaining rabbit pellets under the hutch.
Move the wheelbarrow to your garden area, and spread a half-inch to 1 inch thick layer of composted rabbit manure around your garden plants, using the manure shovel. Alternatively, before spring planting, spread a 2-inch-thick layer of composted rabbit pellets on your garden soil surface, and turn it in to the top 6 inches of soil using a garden fork.