For my first hatch I had around 65% humidity but I had a few sticky chicks and a couple of shrink wrapped so I upped it to 70% on the next hatch and didn't have any problems. Of course, I haven't calibrated my hydrometers, yet, and all 3 of them read something different but I just averaged out the amounts on the 3 of them and figured that I had better results with the higher numbers during lockdown. I am definitely going to calibrate them before the next hatch.
I have had the best luck with the dry hatch method...I have my eggs around 40-45% until lock down. Then I boost it to 65%. This is with chicken eggs, though--not duck or goose.
Alright. I just need to calm down. I think I drank too much coffee.
But seriously, what if the humidity isn't high enough and the membrane looks dry? Could I wet it with a paint brush through one of the vent holes? What if it's too high???
OK, take a deep breath and remember, this is supposed to be FUN! The number one thing to keep in mind is this - you do not want to compromise the hatch for all of the eggs based on one chick that SEEMS to be struggling. It is normal for a small percentage to fail in their attempts to hatch, despite perfect incubator conditions - better to let these go than to doom the chicks who could make it out if we don't get in their way....... This is hard for me to remember in the moment............. And often those that I want desperately to help make it out ok anyway. Set things up to the best of your ability, maybe switch to decaf for the duration of the hatch (just kidding), let go, and enjoy!!!!!