Yes, chicks can take 24 hour from pip to zip. Some can hatch out in a matter of a few hours others can take almost a day. Mine seem to average between 12-18. I have had ealier ones and a few later. I don't believe a hatcher should interfere until at least 18 hours in and then only to check positioning and that's in an incubator, where I usually have a general idea of just when it pipped.
After they pip they are resting and waiting for the vascular system between the chick and egg to shut down. Sometimes this takes most of the day. If you interfer before this happens you can cause the chick to bleed out and loose a viable chick. Also sometimes chicks haven't finished absorbing the yolk and that is happening as well and you can't rush that either.
As long as the chick is not in apparent distress human assistance should be limited. Yes, there are times that we loose a chick before they hatch out, but on the flip side we could cause the death of a chick that would have made it by helping too, so it can be very frustrating deciding when to help.