yes, for some reason a frozen thawed rodent will not smell the same. I don't know if the freezing process changes the cell composition or what, but I have seen animals that will pound pre killed rodents, that will turn and crawl away the second they smell a frozen thawed rodent....even a warmed up frozen thawed. a lot of experienced keepers believe that freezing them, somehow changes the smell of them. and live feeders move, and it triggers the hunting instinct in snakes....so you have to sometimes do this to elicit a feeding response.