so it depends. I normally feed outside of the cage and never had an issue with it... however 2 key facts is 1 make sure the snake is very comfortable with being handled and doesnt get stressed out at all. 2. be sure when handling them afterwards that you support the body correctly without putting pressure on the rat/feeditem which they were recently given.

Now with that said i am only handling them to move them back into their enclosure where I wait 24 hours-ish before normal "fun" handling.

So basicly unless you need to handle them, like the others stated 24 hours is a good rule of thumb.