Whether you’re whipping up an omelet or baking a batch of cookies, one of the great joys of childhood cooking is the cracking of the eggs. Every once in a while, however, Mother Nature has a surprise up her sleeve — or in this case — hidden inside a shell.
In a fertilized egg, the yolk provides a source of food for the developing embryo. As the chick matures, it pulls nutrients from the yolk until it is strong enough to break through and join its peeps on the farm.
Have you ever cracked open an egg to find two golden yolks snuggled inside the same shell? A common misconception is that a double-yolk comes from a “twin egg.” It may be possible for a fertilized double-yolk egg to produce twin chicks, but the eggs we purchase at the grocery store are not fertilized.
While there are some breeds of hens capable of producing double yolks, most double-yolked eggs we discover inside the cartons on our refrigerator shelves are simply biological practice swings. The majority of these double-yolk eggs are produced when a hen is still quite young and her body is adapting to egg-laying.