Depends on what he was on before? Live something I'm guessing

Tips (if was on live rats):

-Prescent room with smell of rat
-Put rat bedding in the snake cage to prescent
-Let F/T rat thaw near snake cage
-Heat rat up with hair dryer or heat bulb (NOT MICROWAVE)
-Do the "zombie dance" (dangle by the neck and dance around or act like it's alive, tease the snake)
-Leave in over night

That's all I can think of off the top of my head.