Wow, that's crazy. I hope not to have the same problem. It was early... tho the first chick hatched was early and is doing fine. 2 hatched on day 19, the rest on day 20. I was totally amazed that they were all done within 24 hours. I figured this would drag out for days!
I still have some things to figure out. I was attempting the "dry hatch" method. In the first 18 days my hygrometer read 40-52%, depending on the weather, but mostly in the 43-46% range. (The incubator is outside... and this is Florida) I added NO water. I decided to do the salt calibration deal to check the meter for accuracy before day 18... and the test said that my hygrometer was reading 61 when it was (supposedly) 75%.
Somehow, I don't buy it. That would mean my first 18 days the humidity was at 54-66%? You can see the lines of my air cells. If anything, my chicks, I thought, were on the dry side. But then, I have no idea how wet a chick SHOULD be, mind you! lol! My second hygrometer (not checked yet for accuracy) was reading only 2-3% off from the other one.
So because I had to assist a couple of times, I did what I could to get the humidity back up quickly after opening the door. My door hinges upwards and is located on the side, rather than on top, so I don't loose so much if I have to open it up. As a result, the humidity just ran away from me and my meters were reading at times 80-90%. Which according to the calibration test, would mean I actually had my humidity over 100% during a good part of the hatching. The chicks never were overly wet, the windows never fogged. In truth, I don't have a clue what was going on there. I guess I just got lucky it all worked out. It definitely allowed me to do some "housekeeping" along the way since I felt the need to release at least some of the humidity! The temperature readings with 3 different thermometers was another trip before I ever got started. I'll save all that for another post!