when i used to breed my own rodents i always used commercial pig feed. they will eat anything and this is much cheaper than rodent food. i supplemented their diet with household leftovers. any veg that was getting too old to look nice i would add to the feed. sometimes i would buy a huge bucket of carrots or apples that are usually sold as horse feed. these are actually fit for human consumption even but often rejected as not being a nice shape for supermarkets.