Humidity struggles???

[Sfraker]

I need suggestions.
I have had three poor hatches this year. In just about all failed cases the ducklings internally pipped and died. The air cells were tiny, many looked no bigger than they do at day one.
I am in NC near the SC border. My house is air conditioned and the incubator is not in the sun, near a window and the ac vent near it is shut. However it is as been incredibly humid out.
I use a digital gauge that I do the saltwater cslibration to ensure I know what it's reading before each hatch.
The first hatch I kept my humidity at 60%. Second hatch I lowered it to 40%.
This hatch I didn't even add water until lock down. Humidity hovered around 20%.
I double check weekly using a wet bulb. Plus the incubator had two digital thermometers that I calibrate.

All three had the same tiny air cells.
These were using a brand new well made cabinet incubator. Prior to this I was using a styrofoam one and had trouble with maintaining heat and humidity.
Help!!!
I don't know what else to do. I have spoken with other farmers in the area that are complaining of bad hatches and are blaming the weather. We have been pushing the 100 degree mark with high humidity all summer. But I hatch inside my house.

People in other areas of the country are hatching my eggs without any troubles.

 

[RubyNala97]

I have a couple of ideas. I also struggled with really small air cells on a batch of call duck eggs that did not want to grow. But I did get them to grow & hatch.
First, mist the eggs twice a day with warm water in a spray bottle. Misting the eggs actually helps them loose moisture. The humidity will spike for a short time but as it falls it pulls more moisture out with it.
Second, when I was desperate with a batch of eggs last August (our humidity was so high outside and even running dry i was at 50%) I bought a container of moisture control stuff from the dollar store. I'll post a pic. I'm not sure if you would need the whole container in the cabinet bator. I have a smaller incubator and would pour some into a small disposable cup and change it out every couple days. It was safe for the eggs and they hatched. Just be careful not to spill it. Maybe try half the container first and if you need to increase to the whole thing. The Dollar Tree sold this one.
That's 2 pretty easy things I can think of off the top of my head. Hope it helps.

 

[Sfraker]

Thank you! It's so depressing to get so close and lose so many. I feel so bad.