If they just hatched they don't actually need to eat for a couple of days, they are still absorbing their yolk, so you have time to go get chick food. That is why just hatched chicks can be shipped across country. If you have eggs, you could scramble or hardboil some eggs and feed them mashed egg yolk. I would never feed chicks Layer if I could avoid it because the extra calcium is bad for their kidneys.
If it will only be a two or three days the layer mash won't hurt them. But it is low in protein for their needs, and has a vitamin/mineral formulation (including the extra calcium) for laying age birds rather than chicks so as soon as you can get them some proper chick starter.