IMHO, those temps are way too high. One must always consider that a thermometer can be off.
Commercial hatcheries use 99.5. That is ideal and what forced air should be. A still air uses the temp of 100.5 IF measured at the top of the egg. That would make internal temp at the center 99.5. So in a still air, it is all about where the temperature is being measured.
An embryo can survive at 98 but can die at 104. If you are measuring 102 and it is off by 2F, it could be 104.
If you're measuring 100 and it is off by 2F, the embryos will survive regardless of whether it is high or low.
Toward the end of incubation, embryos have some metabolism that allows them to deal with larger temporary swings.
The key word is temporary. A long time at high or low temps is always a problem.
I don't think that's the best idea Akrnaf2 has come up with.
Well, this makes me feel terrible. I read the section on temps in still air under incubation thread, and it said to keep temps at 102 in still air. I thought that it was a bit high so I got to 101.3 for the most part. Even still I had 4 viable eggs at day 18. Actually I had 4 viable eggs until yesterday. I also followed what the thread said and kept my temp at 98.5 for the last 3 days, I was using 3 different thermometers. I found my probe thermometer to be most accurate and right near the eggs, at embryo level. All 4 were moving around yesterday, 2 were early today, and now nothing. I'm not sure if they are resting, or dead now! 😞