I intervened.........after reading here about the fan and seeing no progress before I went to bed, I took each egg that was pipped and cracked the shell at the pip and peeled it away. The membrane was dry. I made sure that the poult could breathe. I put damp paper towels around the eggs but left the open ends exposed and returned them to the incubator. This morning, nothing had hatched so I took them to the steamed up bathroom, two at a time and opened them, rinsed them in warm water and returned them to the incubator under a dry paper towel. All the yolks were absorbed. One had expired but the other six are drying in incubator with the three that managed to hatch. The one egg that had no pip, I candled and there was no movement so I opened the end, it looked like it had quit around lockdown.
I had the humidity between 75 and 80% during lockdown so it had to be the fan that was drying them. I have an old Farm Master cabinet incubator. It has six trays but I never use more than two, and that's only because I spread the eggs out or separate them into groups. The fan is made to circulate the air around hundreds of eggs so is quite powerful, I guess. It would have taken me alot of hatching to realize the fan was the problem but I don't hatch much so I don't know if I would have figured this out without the help of all of you. This is the kind of thing that makes BYC so invaluble to me. Thanks for being here!!