The dust alone may not be enough for fast growing babies, what's more important is gutloading your feeders
Lots of leafy greens, bak choi, brocolli, squash etc are high in calcium. There are websites that show the nutrient value of certain veggies which will be directly passed to your animals.
Sometimes if the mother is deficient in calcium then the babies will be more suceptible to MBD.
UV will help however they will not usually bask in it because they are nocturnal which defeats the purpose of daytime UV bulbs.
Hope it helps, perhaps change the diet of your mealies, gut load them like crazy and like previously mentioned leave a dish of powder in their cages at all times
good luck