I have had several eggs that got as far as the internal pip. They were cheeping for 48 hours and then stopped. I know that they were moving because I candled the eggs. Those particular eggs had extremely hard.The chick was perfect inside just couldn't get out. I have a few eggs from a friends chickens with it and one of them hatched last night so there's a blessing in this sad morning. Thank you all.
The last one I lost was just last night. I wish that I had helped with at least creating the external pip since I know it was internally pipped at least 48 hours. There is no sound this morning - I have a camera that can see into the nest box.