What is a Fart Egg?

Several people asked about the "fart egg" that I pictured on 

Instagram and Facebook yesterday. 

I'll try to explain. 

Here is the picture, as posted: 

I found this egg just outside the open pophole of the coop, yesterday, as I was 

closing up. 

I remembered that yesterday morning, I had heard a LOUD cackle while I 

was clear over on the porch, from a hen who sounded very surprised.  Many hens 

cackle, though, as they lay. 

When I saw this egg, I thought to myself "WOW, was that her first?" 

In December I brought home four cochin hens from the National 

Agricultural Center .  All were just coming into lay, or so I thought, 

so... I suspect one or two has not yet. 

"Fart" or "fairy eggs" are described as thus: 

Sometimes called dwarf, wind or—my personal favorite—fart eggs, an egg without a yolk is usually a young pullet's first attempt at laying. These oddities are characterized by their small size, round shape and resemblance to grapes or marbles.Jan 18, 2016

That's from Hobby Farms Magazine. 

Here is the egg this morning, on my kitchen table. 

A fairy, or fart egg, is usually defined by the fact that there is only white matter, 

but no yolk. 

How then, do we explain this?  I could tell the egg was heavier than normal. 

If you look at the picture above, you will see the two fairy eggs are much smaller than a regular egg, 

but I did not think to put mine next to a regular size egg. 

I was stunned to find a fully-developed yolk AND a fertilized chick

embryo in this egg when I broke it open five minutes ago. 

What the heck? 

I have never had a fully developed yolk in one that I remember. 

My guess is that one or all of the young cochins is only just coming into lay. 

I hope this answers all your questions about 

fart or fairy eggs.