[Eriklover555]

Everyone should supplement, not just for RR mixes. No hamster, dog, cat, etc should be kept on the same food with no variation. There's evidence that "complete" food mixes lead to immune system boredom and ingredient allergies.

The reason is that there really is no way to tell the exact vitamin and mineral needs of an animal - most dietary information is anecdotal. There are studies, where they watch the condition of an animal under laboratory conditions, but they can be extremely misleading because of the dosing method of whatever medium they're using. Animal feed is not a highly regulated or tested.

Vary your base mix with fresh veggies (and fruits, if applicable to your variety of hamster). You can also add commercial vitamins to their diet and/or water.