How long can gestating eggs be out from under their Mom?

[Pegasusu]

It looks as if one of our other ducks is chasing off her sister who is broody and has been sitting on her eggs for nearly three weeks. The game cam that we put on them shows that half of her eggs were kicked out and have been out from under her for 8 hours. Do these eggs even have a chance of completing their gestation?

 

[Duck Drover]

I have found cold eggs and even cold babies and been able to warm them up in time. It does not hurt to try. Do you have an incubator or are you relying on the hen to warm them back up?