'Bator temp - slight fluctuation OK?


10 Years
Aug 25, 2009
Quebec, Canada
I'm putting my very first batch of eggs in the 'bator Wednesday!

I fired it up yesterday to practice on the temp & humidity and no matter what I do, the temp seems to be either 98F or 100F (humidity is 86%, it's stable).

Very, very hard to get it at 99F or for it to stay there

My question: is 100F too hot for the eggs?

Is it better to have more heat than less (say 98F)?

Thank you, oh gurus!
I know with Still Air Incubators (No fan/circulation) it's recommended to run at 100-101 degrees F.

But, that's a lot of humidity! For chickens, I heard it should be from 30-50% until lockdown, where it can be from 55-65%. Area affects humidity needed.

EDIT// Oh, also! Temp flucs - I was told not to worry unless it was over 104 or under 97 for over an hour. Other than that, just wait for it to go back to normal because the egg temperature wouldn't have changed.
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OOOPS I meant it's at 86 on the Hygrometer, I don,t know what that is in %... just following the instructions that came with the Hovabator (it's a forced-air model with auto egg turner). Is 100F still too hot or will the eggs develop normally?

Ooh, kay. Usually it'd show a percent next to the number on a hygometer to make sure you know it's humidity.
At least mine does, but then again, mine's a combo thermo-/hygro-meter~

100 degrees is only .4-.6 above recommended I think for Forced-Air, so the eggs will develop slightly faster, but not noticeably much or enough to effect development.
Whew - thanks!!

I will do my best to keep it at 100F, seems to be the easiest thing with this 'bator...

And I found this conversion chart online to get the % of humidity in the incubator when your hygrometer is only a wet bulb like mine... according to this, I have 57% humidity which is what was recommended. I have no idea if it's too high??


Dry bulb reading in Fahrenheit (the actual temperature in the incubator), read left to right, 97 degrees to 102 degrees, on the top line of the chart. Wet bulb reading in Fahrenheit read top to bottom of first column of chart, 56 degrees to 102 degrees. Relative Humidity Reading is calculated by reading down the wet bulb column and across to the dry bulb column.

Yes, fluctuations are ok and completely normal. I'd be more worried if my incubation never fluctuated. I would think the thermometer was broke.

And don't freak out over spikes and dips in temp. They will make it through some tough stuff. I had personally had a new thermometer show 102 and that just didn't seem right (I had to turn the knob all the way up) so I put in another thermometer... it was 112F... for something like 6 hours. Still 100% hatch.

I don't want to steal aveca's thunder but her eggs were without power (durring lockdown) and she was snowed out away from that house. Days later, she got back, turned on the incubator... the eggs picked up where they left off. PS the house was freezing without power.

I will say it until I'm blue in the face, especially on this site... never give up on a hatch and never freak out. Freaking out and messing with the thermostat will hurt more than anything.

You're babies are fine.
Oh wow~! I never used a wet bulb, so I had no idea it was that complicated! Insane.

The area around the bator helps determine how much humidity is needed, since too much can drown the chick and not enough will 'shrink-wrap' it. My area is dry, so I need a little more humidity than people who live in a naturally high humidity area. People incubating in that area can 'dry-incubate' (I think that's the right term?), which means that they don't worry about humidity til hatching.
I've been at 30-40% humidity, and I'm raising it to 60-65% tomorrow (Lockdown).
I have always read and done 50% durring the first 18 days, and 75-80% untill the first hatch... then you drop the humidity back down (in the styrofoam 'bators you just pull the plugs out of the lid) so they don't drown in their little eggs.
You are dead on about that. Area and seasons effect the humidity in the eggs. The weather outdoors should be taken into consideration. Good call.

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