I just had a less than optimum hatch. 14 out of 24 eggs. One chick had trouble getting out of the shell and had to have help. Looks like it may live but it is weak. The membrane in that egg was very thick. I cracked the eggs that didn't hatch to see what had happened with them. 2 had not begun to develop. 1 was a double yolk. 4 had begun developing and quit. 3 had fully developed chicks in them that had not hatched. Those eggs also had very thick membranes. What would cause these thick membranes?
