The chicks travel at 24 hours old. They haven't had anything to eat or drink - they have been vaccinated and have had their beaks clipped (to prevent picking during travel) and that's it. You need to unpack them, show them where to get their water, and get them into their brooder (the warm place they will grow in for a few weeks) as soon as possible so that stress and cold doesn't weaken them. It's common to lose a couple of chicks during transport and acclimatization to their new surroundings. Hatcheries will usually send a couple of extra chicks just in case. We were fortunate - we didn't lose any.
Here we are, taking them out of the box, dunking their beaks in the waterer until they drink, and then they are put in their brooder under heat lamps. There are 60 boilers, plus 10 Plymouth Bar Rocks to add to our laying flock.