Dog food DOES make your rodents greasy and just unhealthy looking in general.

It's hard to find rodent lab block in bulk at a cheap price in Canada. I'm in Alberta and a lot of breeders use 16% UNMEDICATED hog grower. About $16 for 25kg at a UFA store. I'll usually pick up a big bag of bird seed with peanuts and all that fun stuff to mix in as well.