my method: in the morning before work/school, take the rats out of the freezer and place them in the fridge to thaw until you get home for dinner time. take the rats out of the fridge and place them in the same room as the snakes to warm up to room temp (to check if they're completely thawed: firmly press the sides of their heads and their hips; if they're still a tiny bit cold to the touch they're not thawed) and let them smell the prey to get them into feed mode. once at room temp totally thawed, hit them with a hair dryer focusing on the head and offer immediately. that should do the trick!