Egg in a sack?

[Chefads]

This morning i found a fully formed egg inside a whitish colored sack that looked like a deflated ballon. The egg appears to be fully formed with a shell but encased in this film? I also found it in the roosting box beneath a perched bird. Has anyone seen this before? Is it a health problem? The hens are about 2yrs old. I purchased them (4) from a small organic farm near me. They've been laying consistently since having them but i've never seen this before. Thanks!!

 

[sourland]

Some folks have reported a fully formed egg within a second shell. I have never seen this, but it sounds as if a second shell was forming over a 'completed' egg, but the hen expelled it after only the membrane had been 'applied'.

 

[Chefads]

Thanks. The sac was a bit thicker then a balloon and practically the same brownish color as the eggs. Inside was a fully formed egg and everything else seems status quo.