Don't leave them on paper towels more than a day. They will start eating them. There should really be greens in there with them. They literally reach their heads out and eat the substrate before they even break out of the eggs, and they will eat the paper towels. Those new babies should really be in a brooder box. I do six babies per shoe box. I use grape leaves, mulberry leaves, or lettuce leaves as "substrate" in the brooder box, and add in lots of weeds, leaves, flowers, baby opuntia pads and anything else edible to introduce them to it. Its okay if they have big yolk sacs. The brooder box is a good place for them to absorb the yolk sac.