hatching eggs

[alpinefaith]

Hi! I am wondering how long to let my setting hen keep her eggs... She is at about day 25 now, and still no pipping. She did leave the nest once on Day 4, and got confused about where her nest was, so the eggs went cold. I was sure they wouldn't develop, but I left her setting just in case, and when I candled one yesterday, it is all dark inside except for an air sac, so I wondered if the dark part is in fact a chick, and maybe they're late because of day 4? How can I tell?

 

[gamebirdsonly]

They should of hatched by now even with the one day she wasn't on them.