As you probably know, the newly hatched chick can go three days without food and water while it lives off the yolk. I read somewhere, can't remember where sorry, that the chick may not even show interest in food and water until the third day.
I noticed that they start scratchin' around and pecking at things within the first 24 hours. I usually dip their beaks in water to show them where it is.
If you think one of the chicks is not drinking, dip its beak in the water to make sure it knows where it is. Do you have feed laid out at their feet or in feeders?