I would say also keep an eye on the chick's breathing if you can see into the holes and see this kind of movement. If it starts to weaken, you might want to start picking the top of the shell VERY CAREFULLY, as the membrane may be stuck to the chick's fuzz. I have done this before, and gently dribbled warm water from a wet sponge over the chick and into the sides of its shell. If the chick's head is in the bottom of the shell, though you want to be careful not to drown it. As you moisten the chick's fuzz, it should start to wiggle more and eventually work its way out of the rest of the shell.
This has been my experience, so I can't promise this will work perfectly in your case. A lot of it is instinct and just saying when at the right time. I wouldn't go past 36 hours, though. I saved two chicks and lost one in this same situation in my hatch this past April. The one I lost I hadn't started picking its shell off, and it died before I made that decision.