Pip confusion. Help, is this normal

[Lexbarlow]

*UPDATE* checked them and the seem to have moved further back into the shell, away from air sac. Before they were very obviously pipped and now they're so far in it barely looks like they have.
Is this normal? Should I worry they aren't gonna make it?

Hi,
I checked my duck eggs air sacs yesterday about 3pm.
Today I just felt a need to check them again, about 2pm and all of them have pipped (must have a sixth sense)
So I don't know exactly when they pipped how would you work out timing?
The last 4 I hatched all got stuck and I had to help them, losing one before and one that hatched with yolk. I'm just trying to be prepared for when I may have to intervene

 

[Chicken poppy]

It seems fine, but if your worried, many people i have seen *including myself with other animals such as chicks and such* Have done similar things, i think it should be fine and try to avoid getting involved if possible, only if urgently needed. just wait a bit and keep checking on them before helping. Best of luck!