i was reading about feeding rodents on this aussie site, and this is what it said "Freezing,thawing and subsequent feeding of whole prey animals is a common practise among hobbyists and herpetologists,Some experts believe that such food sources should be "gutted" (eviscerated) before they are frozen.This greatly reduces the possibility of generalized bacterial contamination of the carcass.To replace those nutrients within the viscera that would otherwise be lost,the hobbyist can place a gelatine capsule filled with a vitamin/mineral/amino acid supplement into the body cavity before feeding the thawed prey animal to the snake".