Well, I checked my rats a little bit ago. My small rats are about 80 grams. My medium rats are mixed......they are 90-95 grams for the smaller ones and 120-130 grams for the larger mediums. I have a 10 pack. I think my two super eaters can easily handle a smaller medium (100 gram) rats. They are about the same thickness as my BP's. Also, my 1700 gram can easily handle the mediums, but my other girls will stay with small rats. Thanks for all the advice, I think I will stick with a 7 day feeding schedule so they keep eating well for me.