I thought the stuck one was dead for about 6 hours the other day. He pipped day 19 or 20...I pulled him out at almost 22. I waited to grab him when I cleared the chicks out of the incubator...and he was weak and thready and started peeping. The membrane was so dry by then that his eye was stuck open...I had to get him out with antibiotic ointment, tweezers, fingernails, wet napkin...
I have no idea how long they can live in the shell once it has pipped... I am thinking he may be sleeping...they are like babies,,,cry...eat...sleep poop...cry some more...coo
I have no comment on humidity...I have not found a good humidity for my area that is working well with my hatches... Certainly not the one in the manual...