I recently had a thermostat go out on a bator and it had been several days since I had even looked at the temp... the bator was down to 80 degrees when I discovered it and I had no idea how long it had been that way. I got it up and running in an hour or so. The duck eggs only had a week or so left on them so I left the eggs in to see what happened. I had 7 out of 8 duck eggs hatch... 3 days late.