Where are you finding the Rodent 6F for less than Doggie Bag? Here DB is $12.99/40lbs. I used to pay $50/25lbs for M6F. That was a nobrainer for me. They do seem to eat more DB and when I switched and had both feed in the racks they would actually eat around the 6F to get to the DB. Since switching I have noticed slightly unhealthier adults with shorter life span. The production for me increased. I did not notice larger liters but just more liters in general. I even feed DB to my dogs and potbellied pig!! Around my house it's all Doggie Bag all the time.