Hole in eggs

[Dogwoodcreek]

I have a coop with 5 chickens. 2 Black Australorps which are laying another young Australorp pullet and 2 Ameraucana pullets none of which are laying yet. From this coop I typically get 1 egg a day so I assume my 2 Australorps are laying every other day. On every other day the one egg will have a small hole in the shell of the larger end. It does not puncture the air sac. Also, one day this week both hens laid on the same day and one of the eggs was eaten by the chickens but not both eggs.

What could be causing this?

I have straw in the nest box but they move it around to where the plywood is showing at the spot where the egg is laid.

Could the one hen be pecking a hole in her egg after she lays? Or is it the nest box and the way this hen lays her eggs?

Also, if I refrigerate is it safe to eat the egg?

Thanks in advance!