With mice, I guess hoppers can bite, but fuzzies can't. Can weanling rats injure a snake, or is it okay to feed live if that is convenient? I'm guessing rat pups probably cannot bite.
They are 'Red Rat Snakes', so it's not too surprising they'd do well on a diet of rats. I'll check the prices the next time I go to one of the local herp shops. If they aren't much more than $1.50 - mice of all sizes are $1 - I'll try a rat pup and weanling the next time, for my two larger snakes (24 inches and 28 or 29 inches.) So far my WC Miami has eaten a large fuzzy and a small hopper, in the 2 or 3 weeks I've had her, and the Okeetee will eat small adult mice, or most anything up to that size, including leftover pinkies, when I was still feeding pinkies, or whatever else I toss in his cage. The little/hatchling Miami has started growing a lot more since switching off mice pinkies to fuzzies, but he's still eating small fuzzies and probably won't be ready for rat pups anytime soon.