Why Yolkless Chicken Eggs Are Called 'Fart Eggs'

When you're looking for an easy, nutritious breakfast, eggs are an excellent selection. They can be prepared in a variety of ways, such as scrambled, fried, or hard-boiled. And as Healthline explains, eggs are high in protein, vitamins, and antioxidants. Because they're replete with essential vitamins and nutrients, they can also lower disease risk.

But when you crack open an egg, you may be surprised by what you find inside. In some cases, you get a bonus yolk. In others, you may find no yolk at all. As explained by the Homesteading RD, a yolkless egg has lots of names. They're referred to as fairy eggs, cock eggs, and even fart eggs. 

Along with the missing yolk, so-called fart eggs are typically a lot smaller than what chickens normally lay. While strange, fart eggs occur more often than you might think. And there are some interesting myths surrounding them, too.

Why are they called fart eggs?

Many of the names for yolkless eggs are derived from some type of myth or misinformation. According to Cackle Hatchery, the name "cock egg" came from the belief that roosters, not hens, were responsible for yolkless eggs. The small size of the eggs also led people to believe that a fairy was responsible for leaving them behind. As for fart eggs, this name developed because people claimed that yolkless eggs were actually the product of chicken flatulence.

Knowing how eggs develop in hens is the best way to separate fact from (admittedly hilarious) fiction. Purina explains the biological process that produces eggs, which begins with the development of the yolk, or ova. Once fully developed, the yolk makes its way to the oviduct, where it's surrounded by the protective egg white, or albumen. 

This process continues as the yolk and albumen travel through the reproductive track until it reaches the uterus. This is where the eggshell fully forms, which is eventually covered by a protective coating to ward off bacteria. In general, it takes a healthy hen about 24 to 26 hours to lay an egg.

What causes fart eggs to develop?

As explained by Chicken Coach, fart eggs result when a chicken's reproductive system mistakes another type of tissue for an egg yolk. In this case, the process for creating the egg white and shell will happen around the tissue, with the yolk conspicuously absent. 

This phenomenon often affects young hens who are just beginning to lay eggs. It can also happen to older hens, although it's less common. With older chickens, the problem could result from a reproductive issue or a feed that is lacking in the necessary nutrients, which explains why yolkless eggs are often smaller than normal.

Of course, there are numerous egg abnormalities that can derail your breakfast in a heartbeat. Hobby Farm describes a few of these strange eggs and why they happen. If you've ever seen an eggshell that appears wrinkled, it's not cause for alarm. Instead, it signals that the egg experienced trauma as it was forming, and the cracks are areas where it was restored. Eggs can also be completely missing a shell, which may result from a nutrient deficiency in a hen's diet. As for double yolks, this curious but fortuitous phenomenon happens when two yolks make their way down the oviduct at the same time.