Best humidity after day 18

[Black Pirate]

This is my second time incubating chicken eggs. My brother is persistent on keeping the humidity at 90% during the last three days, to make the shells soft. However, I've read that eggs need to lose a certain amount of water inside them. Should I keep it at 90%?

 

[FeatherTay]

This is my second time incubating chicken eggs. My brother is persistent on keeping the humidity at 90% during the last three days, to make the shells soft. However, I've read that eggs need to lose a certain amount of water inside them. Should I keep it at 90%?

I would do anywhere from 65-75%

 

[LadiesAndJane]

This is my second time incubating chicken eggs. My brother is persistent on keeping the humidity at 90% during the last three days, to make the shells soft. However, I've read that eggs need to lose a certain amount of water inside them. Should I keep it at 90%?

90% is too high.
Agree with anywhere from 65-75%
The humidity is not to make the shells soft, but rather to prevent the chick from shrink wrapping during hatch.
The chick has an egg tooth to help break out of the shell.

 

[Black Pirate]

I would do anywhere from 65-75%

Me too. But unfortunately my brother is a persistent on keeping it above 85%. Five minutes ago I just opened two dead in shell turkey eggs. Can it be because of the high humidity?

 

[Black Pirate]

90% is too high.
Agree with anywhere from 65-75%
The humidity is not to make the shells soft, but rather to prevent the chick from shrink wrapping during hatch.
The chick has an egg tooth to help break out of the shell.

Noted.
I found two dead in shell turkey eggs a few minutes ago. Can high humidity be the cause of it?

 

[LadiesAndJane]

Noted.
I found two dead in shell turkey eggs a few minutes ago. Can high humidity be the cause of it?

If they were very wet, then yes this could be the cause. Normally the fluid loss though needs to occur gradually over the first 18 days of incubation. Some people weigh the eggs at different times during incubation and graph these to detemine if the humidity needs to be adjusted. Marking aircell size does the same thing.
Some people do both!

 

[Mellowmalt]

considering the incubator can reach up to 90% indicates that the ventilation holes are closed all the way imo. Mine can reach 85% but 90% to me indicates that the air vents might be closed to increase the humidity which might be more of a concern as eggs need a good air exchange.
So temp needs to be right, air exchange without too much escaping and humidity 60-70% is what I aim for. Once an egg hatches the humidity goes up for me anyway, I focus more on the humidity during the first 18 days, as long as the eggs don't dry too much in this time then the humidity stays high as soon as the first hatches.

 

[Black Pirate]

considering the incubator can reach up to 90% indicates that the ventilation holes are closed all the way imo. Mine can reach 85% but 90% to me indicates that the air vents might be closed to increase the humidity which might be more of a concern as eggs need a good air exchange.
So temp needs to be right, air exchange without too much escaping and humidity 60-70% is what I aim for. Once an egg hatches the humidity goes up for me anyway, I focus more on the humidity during the first 18 days, as long as the eggs don't dry too much in this time then the humidity stays high as soon as the first hatches.

my incubator is homemade. Now that you mention it, I haven't seen any ventilation holes in it at all. Thank you for the info!

 

[Mellowmalt]

yeah sorry without ventilation (or breathing holes) the rest might not have a good hatch but we have all had mishaps so learn from this experience, you don't need to add a lot of holes, I just prop the lid up on my hodemade incubator to leave a little gap, it is easy to add too many holes but you do need some. Good luck