Right before a chick hatches it absorbs the yolk which provides the food it needs for the next 24-36 hours. That's why day-old chicks can be mailed across the country. It also works for hen-hatched chicks. It usually takes 24-36 hours for all the eggs in the clutch to hatch. The first ones to hatch can wait patiently for their siblings to emerge. Mama will stay on the nest that whole time too. Sometimes she'll eat the eggs' membranes to keep up her strength. Some time the next day she usually will take the chicks for their first outing, to eat & drink. Sometimes she'll return to the nest if there are more eggs left to hatch, and sometimes they will, but often those are duds.
Mama knows best! Leave the chicks with her!