I have been ridiculously busy and I haven't been around lately, but just look at the labels folks. The Doggy Bag is practically lab block. It has just a touch more protein and that's about it.
My entire colony is pumping out about 12 pups per litter on Doggy Bag. I will occasionally have losses when moms play tug of war with babies, but they're not cannibalizing them for nutrients. In fact, when a pup dies I usually pull it out of the tub uneaten.
Overcrowding, lack of food, or lack of water are usually the main causes for larger rats killing and eating smaller rats.