A Sawzall is nice, but I prefer a good hand saw, or bone saw. You have more control over the cut and the bone chips. In addition, a good pair of lopping shears works very well for removing legs from smaller big game (Antelope, White tail, etc. - chopping straight through bone or joints).
"Such is the strange way that man works -- first he virtually destroys a species and then does everything in his power to restore it."