How Long ?

[Stacyoung13]

How long can you leave eggs in a carton on the counter, and still be able to hatch them ?

 

[Knighstar679]

7-10 days is the average before they start loosing vitality.

 

[WVduckchick]

7-10 days is best. But I have also hatched eggs that were over 3 weeks old. Viability goes down every day, so set them as soon as is feasible.
But in a case of a lost hen or rooster, for example, I have seen folks incubate older eggs successfully.