I've decided to go the "homemade" route as far as feeding since I want to make sure they are getting all the nutrients and such. I found a very informative website here: http://www.ratfanclub.org/diet.html that I'm going to follow as far as the recipe and probably the "menu" too. Today I went to the store to price out all of the items I need to buy and found that the vitamins were on sale. As you can see on the list, the "Molasses Mix" calls for calcium, magnesium, B12, and chromium picolinate. I found the chromium picolinate and B12, but then I found one vitamin with both magnesium and calcium. I figured that would work, however it also has zinc. The recipe I'm using doesn't call for zinc... but would it be harmful to the rats? I can always return it, but if its safe I'd prefer just using it.