I'd be willing to bet a live mouse would get the mojo working. If she is young a lot of breeders give hopper mice to get hatchlings eating then try to switch over after several successful feedings. After you get a few successful feedings with live mice then you can work on making the switch over to F/T. Also another suggestion would be to buy a cheap digital scale so you can be sure of the weigh loss. Eyeballing a baby can be difficult because a few grams here and there are not possible to spot.