you can leave either a thawed or pre killed feeder over night with no problems, but there are some things you will need to consider beforehand.....
yes, rigamortis will set in if the PK animal is not eaten soon after it's been introduced into the tub. however it will soon subside once it has finished it's process and the muscles begin to deteriorate.
do not leave the feeder (thawed or PK) on the hot zone of the tub. this will cause the feeders to decompose faster. they will bloat extremely fast and this bloating coincides with that (dead animal) smell. once you see any signs of bloating....toss the feeder. this is extremely bad, if the snake eats a bloated feeder it could kill it.
Pitoon