I have always fed my snakes on pre-killed frozen rodents, which are of course are defrosted before feeding to the snake. All of the snakes I have owned or worked with, have accepted pre-killed food from the time they were hatchlings and still eat pre-killed food. Some hatchling snakes will refuse to eat dead food and have to be fed live food and then moved onto pre-killed food. This however would only apply to the first couple of feedings. However this is the exception to the rule. Wild caught snakes will also refuse dead food ( but you shouldn’t buy them remember) Some snake keepers still feed their snakes live food. See below for the pros of feeding frozen food over live food.
Ease of storage
Mice or rats can be bought in bulk and kept in the freezer. No need to go to the pet shop once a week to buy mice or rats
Safer for your snake
Live rodents can inflict horrible wounds on snakes.
Freezing kills internal and external parasites
Feeder rodents are killed in a humane manner ( gas) and then frozen. However snakes are very efficient hunters and will kill a rodent extremely quickly( unlike your cat which tortures a mouse before it kills it).
The notion that a snake has to ” work for its food ” is unfounded in my opinion as a hungry snake will grab a mouse or rat the moment you place it in the cage, will then kill and then eat it. This process takes no more than a few minutes to complete, it’s not like your snake is running in a Olympic marathon.
The Moral of the story is: Always feed pre-killed food