How long should I give my eggs before opening them up?

[Smartie_Pants]

I had 6 eggs shipped to me by Halo. One quit around day 2-3 so I am down to 5. I think one more might be a quitter too. The thing is they were under a hen who tried to get off of them twice. Once on day 17-18 and then today, which is day 20. They got pretty cold both times but they are now in an incubator I had up and running just in case. Realistically, I expect none to hatch, but I want to give them their time. They are supposed to hatch tomorrow, and four have nice air cells, but I can't see any movement. Can you see movement this far in? How many days should I give them after tomorrow?

 

[jvls1942]

I give mine 3 days beyond due hatching date..

 

[Chickenaddict]

Give them a few more days past the expected hatch date, if the eggs get a little chilled while the hen is off the nest that will delay the hatch a bit