Duck eggs generating their own heat?

PaulX

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Nov 15, 2018
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I read that some days into the incubation, the eggs would start generating their own heat, and I may need to turn down the thermostat slightly.

I only got another digital thermometer to calibrate my incubator's thermostat at 7th day of incubation. Back then, my second thermometer would read about 0.5 C (1 F) lower than the incubator thermometer. I noticed that as time went by, the 2 thermometers' reading values would converge, and eventually the second thermometer started reading higher than incubator thermometer. As of now, at day 18, the second thermometer reads 0.5-0.8C (1-1.5F) higher than incubator thermometer.

Needless to say, this morning I was shocked to wake up to see the second thermometer reading 38.0 C, while the incubator was reading 37.3 C (I set the thermostat at 37.2 last night). I adjusted the thermostat down by a further 0.1 C, as I really don't want to risk having the egg temperature higher than 38.0 C.

My question is, am I making the right judgement in tuning the thermostat down?
I mean, these gradual divergence could possibly be due to one of the thermometer malfunctioning somehow.
But so far I'm betting on the odds that the heat generated from the eggs themselves are overheating the incubator, thus I adjusted it down.

The incubator I bought is a local brand here, and I don't know where its own thermometer is located (although it's supposed to be a forced air incubator), whereas I put the second thermometer probe at about mid-egg level, possibly touching or not touching the egg.

What has been your experience? Did you also have to turn the thermostat down as your incubation progressed due to your other thermometer(s) start reading higher and higher?

I know I could buy a third thermometer but I'd have to order it online, and it could take a week to arrive, thus it would be to late anyway so I'm sticking to just one extra thermometer.

Please help. I don't want to get this wrong and end up with deformed ducklings.
 
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WVduckchick

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Slight variations won’t kill them or cause deformities. Consistency is most important. Ambient temps can also cause slight fluctuations, so unless you see a huge increase, I wouldn’t adjust the unit.

Have you been candling and monitoring growth?

I’ve read several studies about lowering temperature for the final few days, and I did it once. But personally I don’t think the bit of extra heat that they generate is enough to bother with tiny changes. Maybe in a super-regulated room, or when conditions are absolutely consistent all the time (like in a lab or such)....but in a house? I don’t think it’s that important. (Think about broody hens and what they go through in an outdoor situation)
 

Ridgerunner

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Have you calibrated that thermometer? The easiest way if your thermometer is a type that can do it is to get an old fashioned medical thermometer that you know reads correctly in incubation temperature range and compare the two. Maybe a cup of water in the right temperature range. That way you will know of the thermometer is reading correctly or not. It's not uncommon for any uncalibrated thermometer to be off a few degrees.

The way our small incubators adjust the heat is that when the temperature gets too low the heater comes on. When the temperature hits the highest mark the heater goes off. Even with the heat generated by the developing embryos that just means the heat stays off a little longer since it doesn't cool as fast.

However one problem the commercial hatcheries have with incubators or hatchers that might hold 60,00 or even 120,000 eggs is that the heat generated by the embryos can cook the eggs. They blow air across the eggs to get rid of the excess heat. That's also why they lay their eggs flat in the hatcher, that exposes more surface area to the cooling air currents.

I don't know how many eggs you have in there or how the incubator is arranged. Are your plugs out to allow fresh air circulation? In a forced air incubator heat build-up from the eggs should not be an issue but is there something about your set-up that won't let the heat escape?

I can't imagine the room they are in being warm enough to cause an issue.
 

PaulX

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Hello,

Slight variations won’t kill them or cause deformities. Consistency is most important. Ambient temps can also cause slight fluctuations, so unless you see a huge increase, I wouldn’t adjust the unit.

Have you been candling and monitoring growth?

The problem is currently the temperature is consistently probably either too high or too low. Incubator thermometer reads 37.3 C 99.14 F, the second thermometer reads 37.9 C 100.2 F. I'm setting the thermostat at 37.2 C 98.9 F, lower than the optimum so that both thermometer read between 37.0-38.0 C 98.6-100.4 F.

I last candled them 4 days ago and all were developing, but back then the 2 thermometers read the same value so I know there was no issue with temperature. I'm just gonna candle them again tonight.

Have you calibrated that thermometer?

I don't know how many eggs you have in there or how the incubator is arranged. Are your plugs out to allow fresh air circulation? In a forced air incubator heat build-up from the eggs should not be an issue but is there something about your set-up that won't let the heat escape?

I can't imagine the room they are in being warm enough to cause an issue.

I haven't calibrated the thermometers, because at the beginning the values they read were very close, but the second thermometer's value has been getting higher each day.

I currently don't have a medical thermometer, haven't bought one because I thought it'd be a bit difficult to use, since (see following paragraph), I need to un-tape the incubator lid, put the thermometer in, tape it again, wait a while then untape, then quickly take thermometer out to read, then tape it close again.

The incubator I'm using looks exactly like this.
https://www.amazon.com/Jannyshop-Incubator-Digital-Automatic-Hatching/dp/B07485X1LF
I'm incubating 24 eggs, the full capacity. The duck eggs are actually too big that the lid can't close, so I'm taping it to seal the gaps, but leaving a few holes for ventilation.
The room is about 30 C 86 F according to my second temperature. It was even higher (33, 91.4) around noon, and will get even higher in a few days if the forecast-ed outside temp is any indicator. Do you suppose that is warm enough to cause an issue?
 
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Ridgerunner

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I don't know why that room is so subject to the outside temperatures but it is what it is. The sun isn't hitting the incubator is it, giving a greenhouse affect? That still would just be during the daytime. That's one of the problems troubleshooting over the internet, you cant see everything and you never know what might be significant. Even when you are looking at it you can't always tell.

Is it possible that the tape and the room being so warm is at least part of the problem? I guess, but if it were I'd expect the temperature to drop at night when the ambient temperature drops.
 

WVduckchick

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I agree, it can be difficult to troubleshoot, so you may just have to guess, experiment, and go with what you think is best. Just try not to overthink it too much.

I have never seen that particular incubator. Looks interesting. But i have seen cases where similar turner motors cause excessive heat. So please take that into consideration. Maybe it’s one motor, but if there happen to be 4 separate ones, that could be a possible cause for concern.
I would move outer eggs inward, and inner eggs outward occasionally.
 

PaulX

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I just verified one thing: the second thermometer, which is actually an inside/outside temperature (see here https://www.amazon.com/Keynice-Technology-Digital-Thermometer-Humidity/dp/B01M9GO20X ), able to read both the temperature near the thermometer body and from the probe which is connected to the body with a wire, well I tried taking the probe out of the incubator and then laid the probe right next to the thermometer body. Both the 'inside' and 'outside' temperature read the same value, which I suppose means this thermometer is accurate.

I also just found this :
http://en.aviagen.com/assets/Tech_C...s/Ross_How_Tos/RossHowto3EggShellTempEN13.pdf
According to this guide (supposedly for chick eggs), the late-stage egg shell temperature should be around 38.0 C 100.4 F if the incubator temperature is set at 37.5 99.5. (The gradual rise of this thermometer value over the past few days then should be because the probe was partially touching the egg shell.) The guide also advises that the egg shell temperature should be between 37.5-38.3 C, 99.5-101.0 F for ideal results. I suppose I'll try to keep my second thermometer value between 37.8-38.0 (100.0-100.4) then, at least for now.

I don't know why that room is so subject to the outside temperatures but it is what it is. The sun isn't hitting the incubator is it, giving a greenhouse affect? That still would just be during the daytime.

Is it possible that the tape and the room being so warm is at least part of the problem? I guess, but if it were I'd expect the temperature to drop at night when the ambient temperature drops.

The room my incubator is in gets morning sun, but all the windows are covered with curtains (so no direct sunlight in the room anywhere), so I suppose that makes it just slightly warmer in the morning than in the afternoon. The minimum outside temperature at night is 25 C 77 F, the minimum room temperature then should be above that. I suppose my room temperature should be quite higher than what you people in the colder climate set your heater to. But if the room temperature was the culprit then the thermometer should have read higher since the first day, not just these past few days, so I now presume it is due to the probe partially touching the egg and the egg generating heat as stated above.
 

casportpony

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I also just found this :
http://en.aviagen.com/assets/Tech_C...s/Ross_How_Tos/RossHowto3EggShellTempEN13.pdf
According to this guide (supposedly for chick eggs), the late-stage egg shell temperature should be around 38.0 C 100.4 F if the incubator temperature is set at 37.5 99.5. (The gradual rise of this thermometer value over the past few days then should be because the probe was partially touching the egg shell.) The guide also advises that the egg shell temperature should be between 37.5-38.3 C, 99.5-101.0 F for ideal results. I suppose I'll try to keep my second thermometer value between 37.8-38.0 (100.0-100.4) then, at least for now.
That's a good article.
 

PaulX

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A little update to this issue, for anyone still following.

Today is day 23, so 3 more days until lockdown.
As stated, I have been striving to keep the reading of the second thermometer between 37.8-38.0 C, 100-100.4 F.
As of now, this has become much more complicated.
As stated before, the incubator room is always warm due to my climate, day time temperature averaging 32 C 89.6 F, and the incubator is full and cramped, meaning the heat generated by the eggs tend to build up inside the incubator, and not much heat can dissipate due to the surrounding air being so warm.

So as of now, even the incubator thermometer itself reads 1 C (1.8 F) higher than what I set the thermostat to. It simply isn't capable of maintaining the specified temperature due to the room and eggs being so hot.
Moreover, the second thermometer (which is touching the egg), reads a further 2 C (3.6 F) higher than that.
So in total, the measured temperature is a whopping 3 C (5.4 F) higher than what I set it.

(back when the topic was posted 5 days ago, the incubator was still able to maintain the specified temperature, and the second thermometer only read 0.5 C (0.9 F) higher than the incubator thermometer.)

Last afternoon, after I went out for 3 hours, I returned to see the temperature shot up to 38.9 C 102 F. The thermostat was already set at 36.0 C 96.8 F before I went out.
I lowered the thermostat setting for a further 1 C 1.8 F, down to 35 C 95 F.
Guess what? It took a further 2 hours to bring the temperature down by 0.5 C 0.9 F.
It's just so much easier to build up heat around here than to lose it.

So now I'm setting the thermostat at 35 C 95 F, which gives the temperature reading of 38.1 C 100.6 F.

That's the current situation, and I really hope I'm not doing anything wrong.
 

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