We too use a half/half mix of the Mazuri hamster/gerbil pellets and a Nutriphase feed. I could be wrong, but I was under the impression that at least some seeds/corn could be beneficial for hamsters, or at the very least are much more tolerated than in chins, as I thought I remembered reading that their natural diet does include seeds and nuts. As far as using chin pellets for hamsters, I don't know that it would necessarily make them sick, but the nutrient distribution is likely different, so a diet of only chin pellets could leave them lacking certain nutrients.