Air sac seems small

[HollyParks]

All of them hatched beautifully!

 

[NorthwoodsChick]

Yes, I meant that....at lockdown I would put them in an egg carton. With that small of an air cell, the chicks will be "wetter" than if the air cell was more towards the norm. Being wetter is like a lubricant and with a high Rh%, it tends to make the chicks get stuck! What this means is sometimes high humidity will make a chick become stuck in one place inside the shell while it's trying to zip. Instead of moving around the shell, everytime it tries to turn it slips back to the same position as before, thus a stuck chick.
If the eggs are in a horizontal position at hatching in an incubator, the egg tends to rotate when the chick starts to zip. If in an up right position, the shell is less likely to move, at least this has been my experience with hatching.