What would you do? Say your hatch is running a bit late and your humidity is dropping below 60%..Do you think you should leave the bator closed or open and add water to get the humidity back up? I kinda thought the purpose of not opening was to keep the humidity up and that dosnt matter if its dropping below an acceptable level? What do you think?
One quick way to add humidity and not leave it open too long is to take a sponge or washcloth (make sure sponge is new, washcloth clean) wet with warm to hot water & set it in. I also use straws to add water through the vent holes on mine. You can rewet the clothe/sponge with the straw also. My problem now is I have lots of wet chicks hatching and the humidity keeps going to high! I had to open and remove my washclothes.
If you don't see any pips yet, it is ok to quickly add water and get it closed again. Once you see pips, do not open it. The chicks will be hatching soon and the humidity will naturally rise from the wet chicks. Good luck with your hatch.
I would open after all are pipped before I'd open just as they were pipping. I've not had any pipped ones die of low humidity unless it got really low for awhile. Otherwise they can breathe through the pip hole long enough for the membrane to soften back up and finish hatching. The ones I've lost had all not broken the internal membrane yet and got stuck because when it dried it was too tough to break so they didn't get out in time to get air. Add water through the vent holes with a straw or tubing. If that's not possible crack the corner and toss a bunch of wet warm paper towels or a wash cloth in there. It will boost the humidity quick but only for a short time.