I'd try rubbing the mouse on the rat. My friends bp was stuck on mice, refused to eat anything but live mice. We bought a mouse and a small rat put them in the same tank and let the tank sit next to the snakes tank for a week. I'm not sure if it was the scent mix from them being housed together or just the teasing scent of food in general, but after her skipped meal and week of waiting she took the rat with no problem and the mouse is now a "pet" and he throws her rats in with it for a few days before her feeding day.