Could you tell us a little bit more about your setup? A picture would also work if you don't want to explain every little detail.

What is most important is the kind of thermometers you are using. If you are using digital probed thermometers than you are good to go. Anything analog is not going to give you an accurate reading.

How big is the enclosure? If it is too big, your baby might just be too scared to eat. What is her behavior like? Does she stay in her hides mostly? Or is she constantly cruising?

Do you move her to a separate feeding box? If so, this might also be causing some unnecessary stress.

I think even fuzzy mice are still too small for your baby. I would start with hopper mice. If you could get her weight in grams that would be helpful for determining what size mice she should be eating.