Well, I had a duck abandon a clutch of eggs after sitting for seven days, after a few hours I decided to candle them, found one that was alive, but at this point the egg was cold. I live off grid, no power, so I put the egg in my bra and that is where it stayed for 3 days until I could figure out what to do. I had a box of grabber hand warmers, so I used a cardboard shoebox with a handwarmer on the bottom, insulated with newfoundland hair, put the egg in there, topped it with more dog fluff, and another handwarmer on top and closed the box. I turned the egg occasionally, checked the temperature of the egg only by touch, didn't have a thermometer, best guess when to change the handwarmers, had a lot of temperature fluctuations over the course of 3 weeks, kept the box on my bed at night so anytime i woke up i could check on the egg, sometimes the egg was very warm, sometimes cool, the egg hatched successfully, she's the duck in my profile pic, she is eight years old. I think people put too much emphasis on constant temp and humidity, all I can say is nature sometimes finds a way.
