Have you ever wondered why they collapse?

[B.P.D]

Don't have a a scientific answer but....
What I think happens is since the babies inside the egg are starting to absorb their yolk their becomes room inside the egg. I think of it like drinking out of a can. when you take a sip of a drink you are emptying the can of the drink and it is being replaced by oxygen. My theory with the egg is since the yolk is being absorbed oxygen is trying to replace the empty space inside of the egg but this causes the egg to collapse under the pressure.
Now, all that I have said is just a thought, it might be somewhat true it might not. Maybe someone else with more insight could shed some light .