I shake the rats for mine specifically so he coils harder. An appropriately defrosted feeder still won't have an issue with structural integrity. He does try to get away with not coiling sometimes until I make him do it properly by wiggling the food more. Once he tried just flopping on top of it instead, which was pretty hilarious. A lot of them will get lazy about it if you let them - it's not an issue. You can convince them to "kill" it or just let them be lazy, doesn't really matter.