Empty, dry egg shells

[Cfm]

I have 4 month old chickens and found 2 eggs in their coop that were rough shells and completely empty and dry on the inside. They were not broken or cracked. Why would this happen?

 

[Wyorp Rock]

Welcome To BYC

A mystery!!

Can you take video when you find the next one? Show the egg(s) and break them open.

Upload video to youtube and provide a link.

Thanks!