How long between internal and external pip?

[reneegrenville]

I have a little silkie x bantam egg in my brinsea mini eco incubator. Yesterday (day 21) I heard chirping from the egg from 5pm to about 10pm. Then the chirping stopped. I am feeling really worried because it is now 11.30am on day 22 and still no noise from the egg. How long does it take between internal and external pip? I can't see any signs of an external pip on the egg

 

[Chicken Outlaw]

I'm curious about this as well.

 

[viktoriacl]

I need to know too!

 

[viktoriacl]

Also how long from first external pip to zip?