The crumply hard eggs question... can the babies pip this?

[Lord Sorril]

What would you personally do, for those who have bred many clutches? And what day should I cut, if I need to?

Personally: If I really thought they would have a problem cutting through---Starting at Day 52 I would check the eggs every 2 days, I would look for small pip marks in *any* of the eggs like pictured in the top egg of the video below at 3:48. Once I saw the first one I would cut a 1" long incision (not window flap) in the top center of the egg running along the longest axis. This is only if I thought there was really an issue--eggs can be rather tough to start with and the egg tooth is quite sharp.