Low hatch rate -mallard ducks

[Swalla]

this is my 3rd hatch of mallard duck eggs. I am using a hova bator 1588 w/ auto Turner. The temp was preset. It seems to stay stable & the humidity as well.
1st hatch was good, 6 out of 10
2nd hatch was bad, 2 out of 8
3rd hatch is currently on lockdown but after candling, I think it will be 8 out of 18!

(They are pipping on day 24)

I’m not sure what’s happening. The first hatch was good IMO. we had just gotten the hova, plugged it in, let the eggs develop & did all necessary steps for hatching. The second hatch, I placed a separate thermometer in the incubator to check it against the one that came on the incubator. But it seemed to be off on degrees & the humidity seemed to be way different. I read on here that the hova temp/humidity levels will be diff bc it reads under the fan motor vs being at egg level. So I thought I would test this. But I’m not sure why it was so different. & each corner seemed to be way off on temp & humidity. So idk what temp/humidity is really accurate.
For the 3rd hatch- I candled the eggs last night. ALL except 2 were moving! Tonight after candling, I only saw 8 that were moving.

What possibly could have happened!? I’m so confused. I’m not sure what I did wrong.
When we checked the eggs that didn’t hatch with the first batch, a lot were almost fully developed. When we checked them after the 2nd hatch, they weren’t quite developed as the first. They still had some of the yolk in the egg.

any advice/help/suggestions is appreciated! This is our first year doing this & my children are loving it but we would like a better hatch rate if possible.

 

[Pyxis]

So firstly, what temperature and humidity settings are you using? When you candle the eggs, do the air cells seem to be developing correctly?

Also, is this is a still air incubator or a forced air incubator?

Sounds like you might have temperature and humidity discrepancies. Get an accurate thermometer like is detailed in this article, or if you can't do that, at least calibrate the ones you have like this to see if they are generally in the ballpark:

Spoiler: Thermometer Calibration

To calibrate your thermometer, fill a glass with ice and leave it out to melt until the glass is half water and half ice. Put your thermometer in the glass, give it a couple minutes to get to temperature, and check it. It should read 32 degrees Fahrenheit. If it does, great! Your thermometer is accurate and you can use it to set the temperature in your incubator.

If it's not right, not to worry, you can still use it. A little math is in order. First, you need to find out how off it is. For example, if it says 33 degrees instead of 32, you know it's reading one degree higher than the temperature actually is. Therefore, when you put it in your incubator, you want it to read one degree higher than the temperature your incubator is supposed to be set at. So in a forced air incubator, you would want it to read 100.5 instead of 99.5, because when it is reading 100.5 degrees, it means the actual temperature in the incubator is 99.5 degrees.

The same is true if it were reading low, so for instance if the thermometer reads 31 degrees instead of 32. In this case, you would want it to read one degree lower than the temperature you need your incubator to be, for the same reasons as above.

Then, calibrate your hygrometer like this:

Then, once you know they're all accurate, or at least know how off they are, take readins to figure out where you actually stand with temperature and humidity.

With them reading differently in different locations in the incubator, it sounds as though you may have hot and cold spots. One solution to this is to switch around the eggs' positions every day so they're all kind of evened out over the incubation period. Another is to add another fan to help stabilize the temperature throughout the incubator.

 

[Swalla]

So firstly, what temperature and humidity settings are you using? When you candle the eggs, do the air cells seem to be developing correctly?

Also, is this is a still air incubator or a forced air incubator?

Sounds like you might have temperature and humidity discrepancies. Get an accurate thermometer like is detailed in this article, or if you can't do that, at least calibrate the ones you have like this to see if they are generally in the ballpark:

Spoiler: Thermometer Calibration

To calibrate your thermometer, fill a glass with ice and leave it out to melt until the glass is half water and half ice. Put your thermometer in the glass, give it a couple minutes to get to temperature, and check it. It should read 32 degrees Fahrenheit. If it does, great! Your thermometer is accurate and you can use it to set the temperature in your incubator.

If it's not right, not to worry, you can still use it. A little math is in order. First, you need to find out how off it is. For example, if it says 33 degrees instead of 32, you know it's reading one degree higher than the temperature actually is. Therefore, when you put it in your incubator, you want it to read one degree higher than the temperature your incubator is supposed to be set at. So in a forced air incubator, you would want it to read 100.5 instead of 99.5, because when it is reading 100.5 degrees, it means the actual temperature in the incubator is 99.5 degrees.

The same is true if it were reading low, so for instance if the thermometer reads 31 degrees instead of 32. In this case, you would want it to read one degree lower than the temperature you need your incubator to be, for the same reasons as above.

Then, calibrate your hygrometer like this:

Then, once you know they're all accurate, or at least know how off they are, take readins to figure out where you actually stand with temperature and humidity.

With them reading differently in different locations in the incubator, it sounds as though you may have hot and cold spots. One solution to this is to switch around the eggs' positions every day so they're all kind of evened out over the incubation period. Another is to add another fan to help stabilize the temperature throughout the incubator.

Thank you for your response. It’s set to be 99.5 but it does go to 99.7 or 99.3. The humidity stays between 40-50% for the first 25 days then I increase it to 70% for hatching. It’s a forced air & has a fan in it. I will try the salt test & see what happens. Thanks again!