This is a personal choice, but I'd assist, but I'm also good at helping a weak chick survive. I'd also guess your chick has already suffocated in the egg, especially if you're not seeing movement at the pip site. A big chick with no air sac will need more oxygen at the point of hatching than before. In the picture it doesn't look like the bill cleared through the membranes. If you open a small hole you can see if it's still absorbing membranes or not as they will be pink and pulsing. If it has not progressed normally and there is a pink membrane put tape of the hole you made, but make sure its getting air from the pip hole. Opening and closing the incubator seems to stop/slow development, so next time don't worry about an unhappy chick too soon. If you do wind up with a weak chick, work hard for the first few days keeping it going. I hatch eggs all the time and every now and then, especially with shipped eggs there will be slow weak chick, but with TLC for a few days to a week that chick will be a normal adult. I just had a saxony duckling that was an assisted late hatcher, that was so weak he couldn't stand and barely alive. Now he is indistinguishable from the rest of the flock. With most slow hatchers it's not a congenital defect but incubation difficulties, so the chick will be normal with extra care. Anyway, it's a guessing game. Usually the best strategy is not to open the incubator during the hatching period which is 24 hours. When the first chick hatches wait until the next day same time, then check slow pips and move chicks out. If there is a really late hatcher, I think to up survival chances it's best to do a really quick incubator clean up, leaving the egg somewhere warm. All the mess from the other chicks creates bacteria soup with all the heat and humidity.