What causes chicks to give up between day 18 and hatch?? FYI Incubation conditions day 1-18: 99.5 degrees +/- 0.2, Humidity 44% +/- 2% only auto turner. Hatching conditions day 18-21+ 99.5 degrees +/- 0.3, humidity 64% +/- 3%. I have 2 digital thermometers in each, the incubator and hatcher, and they have 24 hr high/low. The temps and humidity never varied for the above conditions and usually hovered around the middle of the reported temp and humidity. I put 4 very active Ameraucanas in the hatcher on day 18. Today, day 23, I have one chick. I don't understand what could have gone wrong.