Just wondering.... not informed at all.... but I wonder if having the shell broken up like that prevents the chick from turning inside the shell, to zip out. Too much flexibility?
Read that article above about assisted hatching, but then sit on your hands. I'd keep the membrane moist with...
I'd get them all out of there and into an incubator, or give them to another broody.
I have JUST lost 10 hatching and hatched chicks to two young hens who obviously didn't know what the h*ll they were doing. Some pecked to death, some squashed, some suffocated. I have one survivor.