Rich, I know that Adam feeds his adults small/small rats (between 40-50 grams each) and his snakes eat year round (over 200 snakes).
I feed 2 mice a week, but once my rats get to producing enough to sustain my collection - I'll be small/small rats each week for the adults and rat fuzzies and pups for the rest.
I also experience no fasts in the winter with all 15 of mine.