That's the kicker...the nutritional value of the rodent is inevitably higher on an animal fed a diet specifically designed for a rodent. I too fed doggy bag dog food when I started breeding and didn't have much in the way of trouble but it's just common sense that there is a difference between rats surviving and rats being nutritionally optimum for your reptiles. Use this example: a human being who eats whatever he wants with no regard to nutritional value VS. A human being who eats food based on his exact nutritional needs and supplements with necessary vitamins and minerals. Which is healthier? The first guy will live but the second guy is likely to be healthier and live longer. Besides with rodent block being as cheap as 13.00 a bag for 50lbs why not feed the right stuff?