Backyard Poultry Forum

Hi Benen, the localised temperature variations inside the incubator have always been difficult to manage in my homemade incubators. It is very hard to accurately predict how the heat is distributed by the fan because there are so many variables. Even slight changes in the internal arrangement including just putting eggs in there can alter the flow of air. The placement of the ventilation inlets also has a big impact. While you are experimenting with the first hatch it might be worthwhile to regularly rearrange the eggs to different locations to even out the temperature differences.

That sounds like a great tip! I only have 8 eggs in this time. I think it can fit around 70 once I'm confident of its success. Will definitely look at adding a second heater and fan on the opposite side for future incubations though.

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I think I over cooked the eggs yesterday
Have been fiddling around with the temp sensor location and all of a sudden I checked and my quality mercury thermometer said it was just over 40c. It's back down to 38 now. I guess I'll candle in a couple of days and toss them if they're no good.
I've ordered 2 more computer fans and a larger 12v power supply to place around the incubator to create a more even temperature but it will be a 6 week wait for the power supply from HK.

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Thats why people tend to put plastic soft drink bottles full of water into half empty or pretty empty incubators. to slow the rate of heating or cooling.

However, an egg is a pretty good heat sink in itself and it takes at least an hour to vary even half a degree either way so unless it been several hours the eggs should have been unaffected.

I have said this many times on here. The temperature in the incubator is mostly irrelevant. It is core temperature at the centre of the eggs that is important. I do need to repeat what others have also said on this project. Thirty eight degrees is too hot. Incubation temperature is 37.7 and many incubators run happily at 37 degrees or even 36.5. You do less harm to a chicken with a temperature lower than the ideal than with a temperature higher than the ideal.

The signs of a too high temperature are eggs that pip and maybe hatch a day or too early but are "uncooked" and fail to thrive. Weakened chickens and chickens with curled feet and toes.

Mike

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Retired Now. Have moved and now officially a Tuross Head resident.

Thanks Mike,
At least it's only 8 eggs wasted I guess. I'll lower the temperature when I get home and probably try new eggs from today's lay to start fresh.

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Give them a few more days and candle them. You can put more eggs in anyway while these are still incubating. At some point you have to hatch chickens to see what is working and what is not even with store bought incubators. They rarely ever work straight out of the box and give good hatch rates.

BTW - even with good healthy known eggs, a hatch rate of 85% is considered good.

Mike

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Retired Now. Have moved and now officially a Tuross Head resident.

I've got those temperature controllers. They all look the same but can be very very different.

Yours displays the temperature within 0.1 deg C. However it will only let you set the temperature in whole degrees.
A long while back I got one or maybe two off ebay and they displayed and set the time in 0.1 deg increments.
They were OK and of course very cheap.

So a bit later I ordered about 4 more, I was aware of the ones that only displayed and set in whole degrees and avoided them by checking the photo's and descriptions only to find the ones I got were like yours, display in 0.1 increments set points only at whole numbers.

It is a very hard row you are trying to hoe here. You are trying to keep the eggs at 37.7 by using a different higher temperature. Obviously if you put the sensor at the eggs they will be at 38 so you are trying the sensor elsewhere.
It can appear like you can achieve this, for a while, but it is a furphy. When the temperature outside the incubator changes so too will all the variations in temperature of the incubator including the eggs. The only thing that will remain constant is the temperature around the sensor. Quite possible that the eggs that were at 37.7 at one time of the day go higher than 38 degrees at another time in the day.
IT ALWAYS MAKES MORE SENSE TO HAVE THE SENSOR AT THE EGGS BECAUSE THATS WHERE YOU WANT THE TEMPERATURE TO BE CONTROLLED

What you need to do first is calibrate your temperature controller. These things could be reading as much as a whole degree too high or worse still too low. So what you need to do is get your hands on an accurate thermometer. The only thermometers you will find that are reliable enough for this are medical thermometers. Those little electronic ones that you put in your mouth.

3/4 fill a largish container of water put the controllers sensor in there. Read the temperature on the controller and keep the water stirred as you adjust the water temp by adding cold or hot water. Not trying to control the waters temp, just read it using the controller.
What you want is the water temp such that your controller reads 38.0 and then see what the medical thermometer says. That will give you an indication of accuracy of the temperature controller. You can then use the settings on the controller to calibrate it so that it reads the same as the accurate medical thermometer. THIS IS AN ABSOLUTE MUST FOR ANY TEMPERATURE CONTROLLER YOU BUY!

Having done that you will now have an accurate temperature controller. Now here comes the stinger for benen.
Benen doesn't want his temperature controller to be accurate
What Benen needs is for his temperature controller to read 38.0 when the water temperature is actually 37.7 as measured by the medical thermometer. Then he can put the sensor right at the eggs and away he goes.

So the end result is Benens will look at his incubator and see that it is set at 38.0 and regulating at what the readout says is 38.0 degrees. But Benen will know that if it reads 38.0 then the temperature is actually a perfect 37.7 at the eggs because that is where the sensor is.

So benen see how you go with this using the manual etc., any problems and I will dig out one of mine and give you really exact instructions. Don't panic if you find for some reason this doesn't work, for example if the calibration function only advances in whole degrees, I've still got a few more tricks up my sleeve.

Hi Denis, thanks for the in depth reply! The controller displays and allows me to set in 0.1c increments. I've lowered it to 37.5. I haven't calibrated it yet though, I will have to wait our the incubation period first and then make some modifications to the incubator which include some better shelves for water trays, more fans and also a calibrated temp!
I just candles the eggs and 6 of the 8 have veins, 1 is definitely a no go and 1 is hard to tell because the shell is dark. There is hope yet!
I have the temp sensor directly next to the eggs and along side it is my mercury thermometer. Both read 38 at the moment as I have only just reduced the temp.
Will definitely pursue the current batch but add the extra fans for the next batch as one side of the incubator is around 42c and the other is only 33! The eggs are in a line lateral to the opposing ends so they should all be at the correct temperature until I improve the circulation. Humidity is solid at 45 though which is a plus.

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Still looking well at day 8. They appear growing nicely from what I can see when candling. Humidity is staying solid and the temp is also great at the eggs. Fingers crossed they hatch OK and then I can make some modifications.

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Day 14 and looking great! I'm hopeful!
I'm in the process of designing a new box for the components to increase the efficiency and make it all look less dodgy DIY haha.
I'm thinking of using 2 thin layers of mdf to sandwich a sheet of 12mm foam for the walls and floor, which I can also hide all of the wires inside.
Shorter walls and 3 fans for more even temperature
Mounting the egg turner tray onto a set of drawer slides
Double layer acrylic window with air gap between.

Any thoughts? I'm just finding a lot of heat is lost through the plywood at the moment.

Also, I have a dozen holes drilled in mine for ventilation which I think is enough because of the huge internal volume of the current box. The new one would be much shorter and therefore hold less air. I'm assuming the incubation process uses air and I will need better ventilation. I've never seen the vents on a purchased incubator. How much air generally comes and goes?
I'm assuming it's a delicate mix to keep good air but still keep humidity and temperature correct.

We also just adopted 2 Rhode Island Red roosters to save them from a tiny coop which might be a struggle! They haven't been handled much and are not friendly with us or our rooster
they fought a lot this evening and we had to break them up. Hopefully they settle in over time because I'd love to keep them.

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Hi There;
I seriously advise you not to go down the thin MDF and foam sandwich route. Water and MDF don't mix.
You can paint MDF and use it for an incubator, I do, but you've got to be really smart about it.
You have to keep edges of MDF away from where water will be spilt and from where condensation may occur.

Below is some examples of incubators I have built.
I can do the cabinetry of these in about 30 mins.
The floor and the lid are usually 16 or 18mm MDF. For me they come from one 450 x 1200mm MDF sheet.
I work out the length I need the bottom to be and what is left over becomes the lid.
The walls are always 20mm pine board. So automatically I need 2 cut at 410mm and 2 cut at whatever the length of the floor is to be.
These walls usually are 190 mm but can go 240mm or even wider, up to you I suppose and depends on what is available in your store. I have a drop saw good for about 180mm but I can cut 190 mm with it.

If I am organised enough and want walls 240mm or higher I can get everything cut to size at the Home hardware store.

The MDF that will be the floor gets a piece of Linoleum glued to it before the walls are attached. Spilt water is no longer a problem. The pine handles the humidity but it is nicer to paint it. Pine board is so much easier to screw into than other stuff.

The pink incubator below shows how I use 20x38mm to keep the lid in place etc. Of course you will note that since the lid is much smaller than the bottom I have a piece of pine board screwed permanently over compartment where the wires etc are. The width of this board is not critical at all. In fact if it is too wide and overhangs the end of the incubator it makes a good handle to carry with.

The pink one may or may not have a window in it. If it does then it will be made of thin Perspex cut into a square that is larger than the round hole cut into the lid. Thin Perspex will probably have condensation forming making it hard to see in. In which case the round cover is to keep the cold outside air off the Perspex and stop condensation forming. A rag will do the same trick. If the incubator is using lights as a heat source it also blocks the light from the incubator.



You should get your eggs up off the floor with a perforated metal sheet.


If you are going to have fan and heating at both ends you can buy plastic channel to run wires through and also act as something to sit your metal sheeting on.



The Red incubator is the better design because it has compartments at both ends. It is also autoturn but very different to how anyone else would do it.




If you are going to have fan and heating at both ends you can buy plastic channel to run wires through and also act as something to sit your metal sheeting on.
Nothing solves heat distribution like symmetry does. It has a fan and heater at each end.





Ugly photo but humidity is actually really easy to produce. Just have a Tupperware container with a fan that blows and pushes out the saturated air from the container. Could have some thin acetate sheet or similar to cover the exit hole but I haven't ever found it necessary. Have used this with the humidity controller you have considered. Works great. I have heard of the ultrasonic misters being mentioned no one has ever said the did it and it worked.

Thanks so much Dennis! Your incubators look amazing!
I started building this afternoon. Incubator will be 550X400X250. I have ended up going with 6mm marine ply to sandwich the foam.
I have 2x a4 3mm thick perspex sheets for the window and the egg turner will go on a draw slide for more reliable/smoother operation.
Why is it a good idea to raise the eggs off of the floor with a metal perforated sheet? I have seen that most incubators do this but chickens sit on them on the ground so I don't understand.

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New egg turner to fit 36 eggs (6X6)

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Gluing on the12mm border to surround foam

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Google body temperature of chicken and you get something like the following.



In short very different to the temperatures we use in an incubator.....

Why the raised egg trays?, to allow better circulation around the egg and ensure the egg is 37.7 all way around.

By raising the egg trays you put the eggs up into the main bulk airspace of the incubator away from floors, ceilings and walls where the temperature can vary quite a lot. The bulk airspace is a lot more constant than the surfaces which will vary quite a lot depending how far they are from your heater.
Your main problem with this incubator will be heat distribution, it is naturally going to be colder at the end away from the heater.
What you need to do is blow as much heat as you can at the far wall without hitting the eggs closest to the heater. Multiquip E1,E2 and E3's do this by blowing the hot air down one side of the incubator.

You could do this by Bouncing your "Jetstream" off the floor or ceiling of the incubator thus getting as much heat down the other end without the closer eggs getting too warm.
Or easier still, a heater each end.