If the embryos were already developing and then place in the refrigerator for a few days then the chances of the embryo still being alive are next to impossible. I have had success hatching refrigerated eggs that were refrigerated fresh and had not started developing.
I think waiting till day 5 to start turning them on top of the eggs being shipped probably led to the poor hatch rate. Birds don't wait until day 5 to start turning their eggs. I have hatched thousands of eggs and never waited to start turning them. Just my opinion.