You know what, I recently tried to hatch some eggs (only my 3rd try) and I forgot to put the thermometer on TOP of the eggs to set the temp. After a week, I remembered that the thermometer was supposed to be on top. I moved it on top of the eggs and the temperature was reading 104. I adjusted the temperature, and another week later, I still had 6 viable embryos (out of 11) that were doing just great, which was actually better than I expected considering that I had been collecting then for 2 weeks with no air conditioning in my house (went up to 95 in the house the first week). Then, on the 18th day, when I put them down for lockdown, I had the thermometer on top of the eggs for the first day to adjust the temp again. The next day, I went to take the thermometer out and bumped the darn lid! The following day, I decided to check on the temp again, and I had apparently bumped the thermostat up to 104 again! Crud! All but 1 chick died! I think the first week at 104 wasn't as important because the chicks aren't creating their own heat yet, but right at the end, yeah, it's seems really lethal. I'm surprised I even got 1!