I have one female (1035 grams) that eats 2 mice per week and won't eat rats. My F/T mice are 25g each and my small rats are about 60g each, so she basically eats the equivalent of one small rat per week. As long as she eats consistentely, I really don't mind but I would much rather feed her one small rat. She has put on 140 grams in the last month. I would put yours on F/T small rats if you can get them to switch......should save you time and money.