The Yolkless Egg Phenomenon, Explained

If you have ever cracked an egg open and discovered the rare occurrence of two yolks plopping into your bowl, you may have either been blessed with good fortune or struck by tragedy. According to How Stuff Works, one of the most popularly repeated old wives' tales is that the one who cracks open a double-yolked egg will soon become pregnant. They are also regarded as an indication of good luck according to Wiccan traditions. However, if you're interested in Norse mythology, you might want to watch out, as the occurrence signifies that a member of your family is about to pass away.

While many superstitions revolve around double-yolked eggs, there is another even more bizarre phenomenon that can impact your morning breakfast: a fart egg. A fart egg, also known as a fairy egg, dwarf egg, witch egg, and a slew of other nicknames, as per Atlas Obscura, is an egg with no yolk. While it's very unlikely to end up in your grocery-store-purchased egg carton, discovering a yolkless egg is not unheard of.

Unlike the name implies, these yolkless eggs are not produced when a chicken passes gas. Rather, as Garden Betty outlines, these eggs occur when a bit of reproductive tissue ends up in a hen's oviduct. This piece of tissue tricks the chicken's body into believing it has produced a yolk. Thus, a yolk-less egg is laid. 

Fart eggs rarely end up on grocery store shelves because they often look very different from a typical egg. Atlas Obscura mentions that these eggs are typically much smaller than average eggs that have gone through a normal reproductive process. This size difference makes it easy to pick out from piles of eggs headed for any store shelves. The color can often differ too. These eggs will often spend a longer or shorter amount of time in the hen's shell gland pouch due to the abnormal cycle, so they will often be a lighter or darker shade than a typical egg. 

Just like the double-yolked eggs, fart eggs have their own superstitions attached. According to Garden Betty, these eggs were often believed to be laid by roosters, rather than hens, and they were a sign of the devil. It is said to have to be disposed of by being thrown over the discoverer's roof to avoid any evil occurrences. 

Regardless, these eggs are safe to eat, and if you ever stumble upon a yolkless egg, we deem you very lucky even if superstition does not.