I feed my ball in a separate container, but because of that she knows container=mice coming from the sky.
Now whenever she's in her feeding container she'll stare at the top of the container waiting for mice to drop down.
I suppose you can train snakes in that you can associate different things with handling or feeding. (Sort of like Pavlo's dogs)

I've never heard about scenting with chicken soup until now. I've heard of scenting with hamster and gerbil litter, but not chicken...