Incubation: egg temperature vs air temperature

Hi,

Ok, so it's my first time breeding and, although I have read and prepared as much as humanly possible, when I finally got eggs I start having more questions and doubts on how to best keep the incubation temps.

When you incubate eggs, how much of a difference do you notice between the air temperature and the actual temperature on the surface of the eggs?

Here's my dilemma. I started setting up an incubator over a month ahead of getting any eggs. I had it running and tweaked a lot until I was confident that I could keep a consistent temperature around 89 degrees inside the egg box (air temp, probe close to the substrate). Eggs came, and temps were reading at 88.9. Perfect :) I put the eggs in and left for work. When I came back, I noticed it had gone up to 89.5. Nothing to worry about, I thought, as the eggs might have warmed up the air themselves.

I had also read that some people prefer to measure the temp on the surface of the eggs. So I took my temp gun and measured that. To my dismay, they were at 92-93 degrees, with the max reading reaching 94! :tears:
I immediately started lowering the thermostat a bit over the next 24 hours. Now the air temperature inside the box reads at 87.4, but the egg surface is still at 90-91.

I'm really worried I might be cooking them (if I haven't already), but I'm not sure if I should drop the air temps any lower.
So, I'm looking for the advice of more experienced breeders. Where do you usually measure the temps when incubating? And if you measure the eggs, do you find such a difference between the air temp and the eggs?

Thanks in advance!

Last year I did use my temp gun to check the temps of the actual eggs and found, as you did, that they were several degrees warmer than the egg box temp. I just maintained the egg box temp at my usual 89 degrees and they hatched just fine.

I set the T-stat to whatever gets me 88.5- 89.5F egg surface temp.

I have the thermostat probe tucked between the eggs themselves.

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Originally Posted by meowmeowkazoo

I have the thermostat probe tucked between the eggs themselves.

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this.

and choose which device to trust. the variance in temperature could be caused by an error in calibration. in choosing thermometers, i use an old school but high quality analog thermometer as reference. i only trust digital thermmos that read to within a half degree of the reference....i still use those that fail my test, but i add or deduct the noted variance to get actual temps.

so, eggs produce heat with their metabolism? thats possible.

i would not worry, because people went to africa to check out the actual burrows where female ball pythons care for their eggs and dug them up and took temperature measurements. and its fine. if the temperature and humidity around the eggs are good, its good. the temperatures in the caresheets actually match the situation in the wild, its a year-round hot humid climate wih plenty of rain, so close to the equator that there are hardly any seasons.

its also possible that there is a flaw in the measurement, that the temp gun (for example) is influenced by visible light and gives bright white things a bonus or something.

it would be nice to know if fertilized eggs in development have a real discernable heat output. but i think a flaw in the temp gun is more likely for now.

anyway, whatever may be true, if temps and humidity around the eggs are fine, and the eggs are not touching water, all will be fine. i would still track down the measurement problem, maybe check it out with a temp probe or an oldschool mercury or alcohol thermometer, and check if light throws off your temp gun, just to get to the bottom of it and check what the temperatures really are. maybe, if you have not already, try checking the temps with your temp-gun with the lights off, in darkness. because something is not quite adding up, and forget what i said earlier.... metabolic activity in the eggs would make them 1 degree warmer maximum, maybe. and apart from that, the eggs are doomed to be at ambient temperatures due to the presence of air and the 2nd law of thermodynamics. something in the measurements is weird, and i would guess the error is in the method of measurement, there is no way the eggs could be that much warmer than the surroundings.

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Originally Posted by J.P.

this.

and choose which device to trust. the variance in temperature could be caused by an error in calibration. in choosing thermometers, i use an old school but high quality analog thermometer as reference. i only trust digital thermmos that read to within a half degree of the reference....i still use those that fail my test, but i add or deduct the noted variance to get actual temps.

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that makes a lot of sense. oldschool analog thermometers with colored alcohol or even mercury (red/blue vertical line or silver vertical line in the glass tube) are awesome, especially when they are made for medical-grade or laboratory-grade precision. they are slow but precise.

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Originally Posted by Pythonfriend

oldschool analog thermometers with colored alcohol or even mercury (red/blue vertical line or silver vertical line in the glass tube) are awesome, especially when they are made for medical-grade or laboratory-grade precision. they are slow but precise.

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i rescued mine from a school laboratory that was throwing out their obsolete equipment.:cool:

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Originally Posted by J.P.

i rescued mine from a school laboratory that was throwing out their obsolete equipment.:cool:

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i studied physics and they showed a lot of experiments using really old equipment. it never gets obsolete. for newtonian mechanics they fired a bullet into a block of wood hanging on a pendulum, and the rifle was really old, but the block of wood dated back to 1840 or something, it had notes on the back tracking its weight, and it got heavier over the decades because 2 bullets per year went into it. they also showed experiments with an x-ray emitter in a box made of 4 centimeter / 1.5 inch thick lead glass. i think the emitter was 40 years old or older, and the glass box looked ancient. some old things, a selected few, just keep working basically indefinitely until they break. only fools throw them away.

Thanks everyone for the great replies.
After fiddling a bit with .5 degree changes up and down, I think I have now settled for 88 degrees air temp, next to the eggs. This is giving me readings of around 90 on the eggs surface using the temp gun, so I feel that's a good compromise.

I did calibrate the probed thermometer before using it. I calibrated 3 of them and chose the one that got closest (+0.2) to go inside the box.
The temp gun might be off, but I had compared temps between them before and they were much closer.

Right now I am guessing they do emit a little bit of heat, and the rest is probably due to error in measurement.

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