I had a 32 gram hatchling this season. I would skip mice all together (ones without eyes open are too small and ones with eyes open could bite the baby and further delay feeding normally). I would get him out of the deli cup and into a small bin with several tight hides and wet paper towels and water dish of course. In 24 hours I would throw in a live rat pink (5-6 grams would be great) and leave it overnight. If it did not eat that I would wait til it shed and offer again the same type meal. If it refused I would thump that pink and attempt assist feed. If it takes it great, leave it alone and repeat live then thump then assist in 3-4 days. If it refuses the assist feed I would not assist feed again for at least a week but better two weeks but still offer a live rat pink every 3-4 days. My 32 gram hatchling did not take his first meal until he was a month old. That was after offering live every 3-4 days and two failed assist feeds. He finally took an assist feed just days before I was going to go with a pinkie pump method (quite yucky and I hate to do it). Stress can be hard on a hatchling.