Feeding Baby Axolotl

I raced home from work tonight to check on my baby Axolotls, (and greet my lovely family, of course)! My biggest concern, as this is my first time raising baby axolotl from the egg, has been feeding them. So far I have fed them frozen blood worm, but as they are so tiny (about 10mm), it is difficult to really see if they are eating much of it. I am mainly being guided by the fact that the four hatchlings are active at four days old, my fear being that they will starve, as I have been unable to provide them with a live food source. So this morning I decided to try giving them some protein rich, boiled egg yolk, just to give the precious ones an alternative option. It was blood worms again for dinner tonight. Mean while, the five 'late developers' are still wiggling inside their eggs. No casualties so far, fingers crossed!