If they are still peeping and wiggling, I'd leave them in there for another 12 hours. If there isn't any progression at all by then, pull an egg out and have a look at it. Either going into the air cell on the top or opening the hole up larger where they've pipped the shell. If you wet the membrane a little with a q-tip, you can see if they're any active veins within the membrane. If so, it's too early, the yolk has not yet been completely absorbed, they'll bleed if you help them out and will likely die. Leave them be and really up the humidity with sponges etc. If you don't see any active veins, they're ready to come out. If they were due to hatch a long time ago and they are still alive, I usually assist then. If they are being artificially incubated, you got to remember it isn't truly natural, so I always justify it as being the possible cause of complications and not simply "genetically weak" chicks. It could be because of the incubator or other factors. I've assisted many, many chicks. Mostly due to incubator flaws and malfunctions (I've since purchased a very nice bator
) The key is to know when they are ready to come out (veins dissipate, yolk is fully absorbed into the naval.)
