I appreciate everyone's input and being enamored with the pipping/zipping process - but why?
By day 20+, there isn't anything you can actually do. The birds hatch or they don't. They all won't hatch in most cases. The weak ones probably shouldn't hatch.
I recommend, if you have embryos full term at 19-20 days, raise the humidity, sit on your hands and count the chicks out by day 22.
Assisting chicks that don't hatch on their own is possibly a way to continue genetics of chicks that can't hatch on their own.
Chickens have been hatching for millions of years without human intervention. Let's not make the species weaker.
Much less stress.
I'm sorry if I offended anyone but that's just the way I feel.
I feel everytime i help one they die hours later so i no longer help except recently i had to evict two chicks out of their shells as they were way to big to hatch both are doing well but they are my special chicks their grandkids to my fav glw roo that was killed by dogs two years ago any other egg i would of just let it be