It is possible to compost animal mortalities or butcher waste in order to dispose of the waste. The New Jersey Department of Environmental Protection has guidelines (N.J.A.C. 7:26A-4.5(c)) which should be followed when composting. For other information contact the New Jersey Department of Agriculture.
The finished compost material can be used on hay, corn and other field crops, tree plantations and forestland. It should not be added to crops such as fruits or vegetables directly consumed by people. Neither should it be available for resale. The process includes layering the dead animals or butcher waste with wood chips and manure. A deep bed of wood chips should be made and the animal should be placed in the bed with a layer of manure and covered with another deep bed of chips. The pile should be left alone for at least six months. At the end of this period the only material remaining should be bones and maybe a little hair/hide. Below is a picture of how the pile should be made and another pile showing any remaining material after uncovering.
Before Uncovering Pile After Uncovering Pile
One of the concerns about disposing of dead animals is the risk from disease. Any animals dying of a reportable disease should be reported to the New Jersey Division of Animal Health prior to composting.
For more information please contact the Cornell University Waste Management Institute. Or see a factsheet produced about mortality composting: Natural Rendering:Composting Livestock Mortality and ButcherWaste.