Watch it and give it up to 24-36hrs to see progress. If the bird has not got most of his body out after 36 hrs, you MAY need to help if he's acting too weak to dig anymore. Usually if the beak is out, they're going to be fine. They get a brown bag lunch that last for 72 hrs when they're born.
The hatchling has to escape SLOWLY by chipping away small pieces of shell, and tearing thru membrane slowly and letting that dry out so that the membrane does NOT bleed him out. The membrane is still full of blood and has to dry out as the animal escapes. Finally the bird appears and the cord is still attached. The bird will be connected for a few hrs sometimes until the cord dries out and breaks off. DO NOT cut the cord...let it dry and break on its own.
I have had to 'help' a duck hatch and its a very delicate proceedure. Tiny flakes of shell at a time along with very very small cuts in the membrane if the bird can;t cut thru himself. At the first sign of ANY bleeding (if you help) STOP and let it dry for a couple hrs.
Just give it time. Anywhere from 24 to 48 hrs. Then the hatchling may take another 24 hrs to even begin to stand...he'll be weak, wobbly and shaky. Once he CAN stand, have a shallow dish of water for drinking and some chick starter thats been wetted so its mushy.
Don;t allow him to be aroudn water more deep than his beak...they're dumb as a rock when born and can drown themselves in the drinking water. After a day or two, put him in the sink and let him clean up a bit...but watch so he does not drown. Keep the water shallow and never turn your back.
be patient. resist the urge to jump in and help. Its a slow arduous process and hard to watch. if he got that far...he's likely to be ok.
Good Luck and Congrats !
You DO know that you may be raising that orphan yourself right? if he/she was not hatched by a hen, they (grown ducks) will likely reject the duckling and even attack it if you allow the others to have access. They'll treat it like an intruder. Getting a 'friend' will be very helpful for the baby.Even chicks that are similar in size/age. They do not do very well alone.. I had to go buy a friend for an orphan I hatched. The duckling was totally stagnant in her growth until she got a friend to hang with, then she blossomed and grew like a weed.