So you feed her ONE mouse every three days? That is ok and it should put some weight on her faster. When you feed every three to four day, it is said to cause digestive problems (but I have never seen any proof) by some and to others it is perfectly ok. Just make sure when you are feeding you are useing a smaller sized rodent to limit digestive strain on the snake. If you start feeding the max size rodent every three days and up your temps to help digestion then that is Powerfeeding, which may or may not be too good for you snake (it is always under debate).

Have you tried offering both mice in one sitting? I have a 300 gram male that has been pounding 2 adult mice every five days since he was 240 g. Give multiple mice in one meal a try. It might keep you from worring about feeding every 3 days.