Egg cracked but no real air hole, how long till I worry?

[Mama2B&D&...Chickens]

I don't even see any movement at the cracked sight when I hear the chick chirping?

 

[howfunkyisurchicken]

Its fine. It takes ALOT of effort to pip (break thru the shell). They usually rest for quite sometime after. When they zip, sometimes they'll go halfway and take a break, sometimes they come all of the way out. They'll be exhausted after hatching, so don't expect much from them after they're out either.
Incubating is an exercise of patience. Good luck