What is going on with this egg?!?

[Hnbugler]

My hen laid this very unusual egg today.. it feels like a fully formed shell with a crack on it, but what is on it?! It’s very thick & slimy. I also found some of this membrane like stuff in her poop when cleaning the coop.

Has anyone else ever had anything like this happen?!

 

[Eggcessive]

That is a phenomenon called an egg within an egg, which basically is a glitch in the egg laying process. It can be fairly common. It happens when an egg is going down the tract, then reverses, and gets covered by a second egg. Hopefully, it is nothing serious. Here is an article about this:
https://backyardpoultry.iamcountryside.com/eggs-meat/how-a-chicken-lays-an-egg-inside-of-an-egg/