I agree dog food is definitely not the quality of rodent block. We feed kent but also offer sweet mix horse feed and hog feed as well. Occasionally my rats get a bag of doggy bag if I'm out of rodent block but it's kinda funny how they will only eat it when nothing else is there.
On a side note we feed grain free to our dogs and I have often wondered if this would be good for the rats but at 50.00 for 30lbs I'm not likely to try it out anytime soon. Lol