As Rich said it's not a matter of whether it is a high quality or a low quality dog food. The problem is that it's dog food not rodent feed. The nutritional needs of the two are just different. Look at it this way, if you have a pedigreed champion dog and you feed him the best dog food money can buy, that same feed wouldn't work for your thoroughbred race horse. Could he live on it? Most likely but he won't what he needs to perform at 100% from it. That's what you're trying to do with your rats, get them to produce as many healthy offspring as possible. So it only makes sense to buy a feed that is nutritionally formulated specifically for a rodent.