they're brought up on natural and nutritious food to make them 'feeder' worthy,
Many at home feeder breeders, or even "larger" scale feeder breeders use dog food as a main diet. Calling dog food natural is a joke. Have you looked in what's actually in dog food? Some real nasty stuff! There are very few high quality dog food that lack these "unwanteds" and to find these brands in Canada? Well good luck!
Feeding a rat/mouse fed dog food isn't that far off from "steroid" chicken.
However, rodents are whole foods, whilst chicken is not. Snakes need the fur and organs.