I suspect gram per gram, a rodent is a rodent...

While I surely believe that different foods will have different nutritional values, I just don't think that mice vs rats, or even rats vs rabbits, is enough of a difference to change their nutritional value (other than mass of the prey item).

Breeder mice are easier to deal with but the mouse has to be older to be of a usable mass. Rat breeders are more work to keep but their offspring can be used as food at a much younger age (compared to mice).