I came home to find 8 of my 15 eggs hatched and 4 more zipping. One of the zipped eggs does not appear to be moving at all and the feathers and membrane look kind of dry compared to the other 3 that are zipping and moving. I have not opened the incubator and the humidity was at 66 when I got home. I just used a probe through a air vent to tap it and there was no movement. What would cause a chick to get so close to hatching and then die?