Air sacs different sizes duck eggs day 23?

[MotherDucker3]

So 2 of the eggs appear to have died I think. They were the ones with smaller air sacs.

So far 4 of them have internal pips. Hoping they all hatch safely

 

[ChickenCanoe]

I'm guessing a difference in porosity. The ones with a large air cell could also have a tiny imperceptible crack.

 

[MotherDucker3]

I’m like 99% sure this is dead right?

 

[MotherDucker3]

There’s no visible veins