It can take up to 2 days for a hatchling to break out of an egg. They are oriented "sideways " in the egg and appear "folded" when they hatch. Many have visible yolk sacks and should be kept in the incubator until the yolk sack absorbs.
It can take 2 weeks or longer before they start eating. During this time they are living of the yolk reserves. I keep them in small Rubbermaid containers until they are actively feeding.
I use the same Bed-A-Beast/ sand substrate that I use for the adults. Its important to not let the substrate dry out. Also provide a shallow dish of water for soaking and drinking.
I feed the hatchlings daily. They get the same food as the adults. Since most of what they are fed is weeds and grass, I don't supplement them. I have always had smooth growth and firm shells. I also soak them at least every other day.
If the weather permits I bring them outside during the day. They are outside at least twice a week. I use 55 gallon Rubbermaid containers that are planted with weeds. The top is securely covered with hardware cloth and 1/2 is shaded.
A size comparison as they get older
Calcium is very important for hatchlings. I feed only high calcium weeds and greens. I also dust the food with TNT™ and keep cuttlebone with them at all times. They may ignore the cuttlebone most the time, but they do eat it when they require extra calcium.