misting the eggs during incubation?

Misting is an attempt to mimic the natural conditions of a mama duck coming back to the nest after a bath. I don't do it usually, but Dave Holderread recommends it for optimal hatch rates, so I am willing to bet I could raise my rates even higher if I did.

One thing to keep in mind though (also per Holderread): Misting has the SAME effect, in terms of air cell development, as LOWER humidity. It sounds counter-intuitive, so I feel like I really have to emphasize this. When you spritz the eggs, it is NOT the same as raising the humidity briefly--in fact, it's similar to LOWERING the humidity for about a day in terms of air cell effect. The reason for that is based in the molecular structure of water, specifically it's polarity (as I understand it--if someone understands this more clearly I would love to be corrected ), i.e., the fact the water molecules are attracted to one another. So when you spritz an egg with water, the moisture inside is attracted to the moisture outside and passes through the shell to join its brethren and subsequently evaporate.

As such, spritzing can sometimes be a useful tool toward the end of incubation if your air cells are not developing well and you can't lower the humidity any further. It's also useful if you live in such a humid environment (like a rain forest, lol) that you simply can't get the humidity low enough to develop the air cells effectively.

Of course, attracting water through the shell is not the only thing spritzing does, and I'm sure if Holderread does it regularly there is a good reason for it. However, I am lazy and happy enough with my 85-95% hatch rates to not bother.

 

I do mist my duck eggs too. It works well for me.

 

Doing some reading on this subject before I try hatching my first duck eggs...
When do you start misting daily, and when do you stop ?