I can't understand why this is happening. I had on chick hatch on day 19 and everything went perfectly fine. Since then 4 chicks have die on day 21 still with unabsorbed yolks. They did not internally pip and we're positioned correctly for hatching. When I looked inside to see what happened it almost seems like they run out of room in the egg and just died. Any information would be helpful. The last egg was alive 2 hours ago and I came home and it was dead. They didn't look dehydrated and Temps and humidity have been steady at 99.5 degrees and humidity at 45-50 % throughout and up to 65% during lock down. I'm using a still air incubator with eggs from my chickens of various breeds.