put it back in lockdown and just look but don't touch for a day or two.
Other than the air cell, does the rest of the egg look dark? If you can still see the outline of veins in the clear liquid, your chick isn't as far along as the calendar says. Search for some of the candling eggs threads to see where your egg is in its development stage.
This is going to sound like a dumb question, but where did your egg come from and how was it stored before you set it? If it had been refrigerated, that could explain the delay as the egg returned to room temp then incubation temp.
Other than the air cell, does the rest of the egg look dark? If you can still see the outline of veins in the clear liquid, your chick isn't as far along as the calendar says. Search for some of the candling eggs threads to see where your egg is in its development stage.
This is going to sound like a dumb question, but where did your egg come from and how was it stored before you set it? If it had been refrigerated, that could explain the delay as the egg returned to room temp then incubation temp.
