I feel silly for asking, but...

[I Dream 0f Chickens *U*]

What exactly is a pip and a zip.

I have a pretty good idea, but when do they each occur?

 

[poultrycrazy]

A pip is the whole they make first and the zip is the crack they make around the eggs before they push there way out if im correct.

 

[lovin my birds]

A pip is when you see the first hole the chick has made in the egg. A zip is when the chick makes a row of punctures so that it can puch part of the egg off.

Pip is first and zip is second.

 

[I Dream 0f Chickens *U*]

What is it when they break into the air sac?

 

[ChestnutRidge]

Here's a pip (on egg labeled "EE6"):

And a zip:

 

[ChestnutRidge]

I Dream 0f Chickens *Ü* :

What is it when they break into the air sac?

I've seen that referred to as "pipping the membrane," but as it is not visible unless you are candling the egg and see the beak in the air sac, "pip" usually refers to pipping the shell.​