How long can a hen be off the nest?

[ceeceeholt]

My second leghorn to go broody, got on the wrong nest some time today. My were question is, how long can she be off the eggs before they are no longer viable? I was gone most of the day and when I came back she was on the wrong nest. The eggs were not cold, but they were not warm. Anyone know? Thank you all

 

[sourland]

Given the present temperatures, I am fairly certain that the eggs if fertile will still hatch. Understand that if this keeps happening the end result may be far different.