Before they hatch the chicks absorb the yolk. They can usually live off of that yolk without eating or drinking for 72 hours or more. It does not hurt them to eat or drink before that 72 hours is up, many will. But they are often not that hungry or thirsty at first. Often they are not hugely active the first couple of days after they hatch. Many tend to stay somewhere warm but after two or three days they are running everywhere.
The one that you helped may be tired and really need some rest. There is usually a reason you need to help them, there might be something wrong with it. I'd keep it warm and watch for a while. If it doesn't perk up by tomorrow I'd try putting a drop if liquid on the tip of its beak using a medicine dropper. It should twist its head around to drink it. Keep feeding it as long as it will drink. Some people use electrolytes you can get at a feed store, some dissolve sugar in water. I use hummingbird liquid since I always have some handy. The idea is to get something inside it to keep it hydrated but mostly to give it enough energy to eat and drink on its own.
Good luck!
