Actually, digesting a larger prey item can be more taxing on their system than two smaller ones that equal the same volume - as the two would be less dense than the one.
However, for an animal that is an opportunistic feeder in the wild, I doubt seriously that there's much stress involved in being fed multiple prey on feeding day.
Bottom line - feed what your snake will eat, and what's convenient for you. Don't worry about other people's opinions. If multiple mice work well for you - feed multiple mice. If one rat a week works well for you - feed one rat.![]()