I think what you have is called a "wind egg". I recently had a very tiny egg appear and did some research. That tiny egg has no yolk and it's really a "blip" in the reproductive system. It may or may not have anything to do with stress or fear or trauma. It just happens!

I know that stress can affect egg production. I recently had some serious tree harvesting around my chicken coop where there was alot of heavy equipment and giant saws and skidders taking out 100+ year old trees. My girls (14 of them) did not lay for almost two weeks after that trauma!!

I think you will find the attached link as interesting and illuminating as I did!!

Here is a link that might be useful: Odd Eggs

That was interesting. A "fart egg"! I'll have to crack it, I guess, to confirm it has no yolk. Thanks for sharing your research.