Too hot? Too cold?

[hfchristy]

I've got a dozen duck eggs in the incubator which frustratingly has a Celsius thermostat. It's currently set to 37.7.
I've also got an egg-o-meter in there and a wifi temp/humidity sensor. Egg-o has been reading a steady 100.2, but sensor was reading 99. Figured they averaged out okay and eggs seemed happy.
Today, they've swapped. Sensor is up at 101.5 and Eggo has dropped to 97.5. Incubator says nothing has changed.

Eggs do NOT seem happy now. I think I've lost several over the last 12 hours.
But is it too hot? Or is it too cold?
At 3 weeks, which is more likely to be deadly?

 

[Jpat]

at three weeks heat is a killer, at that point they can generate a little heat themselves and slightly raise temps of an incubator, especialy if it doesn't have any air vents

What kind of incubator are you using? Forced air and still air have 2 different temperature requirements

37.5 to 38.3 is ideal for a forced air incubator

The most important tool in incubation is lots of calibrated thermometers

Here is a quick post I made about calibrating thermometers

https://www.backyardchickens.com/threads/big-bator-build-with-baby-photos.1345445/post-22123698

 

[hfchristy]

I'm not sure any of my thermometers are up to boiling.

For the non-mercury, electrical thermometers is there a way to calibrate?
Do they sometimes just go bad? I'm so confused by one suddenly reading nearly 3 degrees less than before while the other is suddenly UP a degree and a half!
It's especially weird that both of these changes happened at the same time - while the incubator says it's holding steady!

I just realized that the hygrometer also has a tiny temperature display. So, yet one more uncalibrated data point.
It's saying 36.3, so about what the eggometer is telling me.

 

[hfchristy]

Incubator is a little forced air "hatch mate"

 

[hfchristy]

Looks like the thermometers are BOTH correct. There really is a FOUR degree difference in the incubator, in spots 3 inches apart.
I grabbed another wifi sensor, identical to the first, and put it in there. At first they were totally in sync. Then one of them dropped suddenly after I turned the eggs. This morning I finally thought about it maybe being positioning and I swapped them. Temperature readings swapped, too.

These eggs had wonky air cells, so they started out upright in egg cartons with the bottoms cut out.
I'm using one of those to keep the thermometer up about the same height as the eggs. The two sensors have ONE empty cup between them. It is crazy to me to think that that tiny distance apart the temperature could be so different!