Don't make any holes in the shell. I have had the ducklings pip internally and take a week or longer after the internal pip. Most of my ducklings are wiggling and chirping for a few days before the first external pip, which looks like a tiny dent in the shell, then take 12 to 30 hours to finally hatch. The air cell will expand to take up almost a third of the egg by the time they are ready to hatch and the air cell will be in almost a u shape, I'll try to upload a picture of one of mine that's a few days from hatching. Try to crank the humidity up to 70% until they pip externally the temp should be at 100 degrees F I also lightly spray the eggs with room temperature water for the last few days before hatching only once in the am and again in the pm before bed. I've only lost 2 eggs out of the 14 that have hatched so far. The first one was due to my over-excited 5 year old punching a hole in the egg the second was shrink wrapped due to the temp in the incubator spiking to 110 when my ac broke luckily the other 2 in that bator are okay but I upped the humidity just incase. The one I lost was closer to hatching than the other two. When they do pip try to up the humidity to almost 80% duck eggs are thicker than chicken eggs and the ones I hatched with the higher humidity seemed to have an easier time. So far the temporary increase in humidity hasn't hurt the later hatching eggs.