My experience is this; I deal exclusively with ball pythons, and they all ONLY eat rats, so the mouse debate is not pertinent here. What I have noticed is this. When I pick up a few rats from my friend, who also breeds rats for feeders, she only feeds low-grade dog food, same crap you guys are talking about. Her rats, same pysical size to mine (which all eat breeder Mazuri 6F), are approx. 40% lighter' meaning if you put two comparable-sized rats next to each other, one hers, one mine, my rat (the Mazuri rat), will be 100g, while hers will only be 65g. Just my experience, that an the fact that I pick up Mazuri for $19.10/50 lb. bag.