Dumb question

[Jay_Bunny]

eggs breath through the shell if they were going to suffocate they would have don so already.

Once the babies have pipped they no longer breathe through the egg. They are breathing air. The OP was asking if they'd suffocate due to limited availability of air in an incubator.

Once my eggs pip or are cut I check on them a few times a day which exchanges the air
I wouldn't worry too much about it. They don't use a lot of air when they are so small.