If the chick has been stuck for 3 full days without progress, it is possible she is actually stuck/glued and unable to zip the shell. If this is the case, she will eventually expire without your intervention. I suspect the membrane has become dried hardened and stuck onto the chick, since the shell has been open for 3 days...
Personally I am of the mindset that I will intervene when absolutely necessary. I have already interfered with nature insofar as to incubate them artificially (in artificial conditions, in an artificial turner), at this point I really owe it to them to see them through what I did to them. If I let a hen brood the egg, it probably wouldn't get a dried out stuck membrane. It's kind of my fault for creating the situation, as I see it. Anyway...
Please read this article if you choose to intervene:
https://www.backyardchickens.com/t/9316/intervention-helping-your-chicks-hatch
it is a personal decision no one can make for you.