When do chicks drown?

[BawGock]

Are drowned chicks a result of fluid building up throughout the incubation or is it a result of high humidity during the last few days of incubation.
I've only had one chick that was obviously drowned in my first 3 hatches and it was when I was hatching a large amount of egg in my 1588.
I always attributed the drowned chick to the run up in humidity we had with all the babies drying off in the bator but maybe the fluid built up earlier possibly?

Carolyn

 

[MagsC]

This past hatch I had reasonable humidity (anywhere from 40 to 55) and then upped it the last three days.
The egg has to lose just so much before the hatch, so I would think you are right, its an ongoing thing?

 

[BawGock]

Yeah, I run mine during the first 18 at the same humidity that you mention and day 18-21 at 55-65%, air cells look great at lockdown.
But only had the drowned chick on my largest hatch. Even with the plugs out the hatching chicks ran it up to 80+%.
It's made me a little scared to go over 2 doz on a hatch though I know the 1588 is made to do twice as many as that.
Thanks

Carolyn