I blend up 50% high quality dog food, 25% Rodent Chow (Harlan Teklad), and then I make up the rest (25%) in Kashi Brand Cereals, Oatmeal, Cat Chow, and pretty much any other grain you can find in the cabinets.

I've also heard of people using fish flakes, noodles, etc. There is a reason I use dog food over cat chow as the main stable. I've heard of several people losing entire colonies (especially with Dubia Roaches) from too much protein.

It seems to be a good diet for them, they grow fast, and have a fairly high reproduction rate.

I also feed them fruits (citrus is supposed to be good for reproduction), and fresh vegetables (like Turnip, Collard, Mustard Greens, Carrots, etc).

Hope this helps.