Double Yolk Eggs Explained

The woman at the other end of the phone sounded worried.

Almost all the eggs in the carton she'd purchased contained two yolks. What was wrong with these eggs?

And since she assumed something had gone wrong somewhere, what would happen to the hens, where the problem no doubt lay (no pun intended)!

I assured her there was nothing wrong with the eggs or the hens and that occasionally hens lay double-yolked eggs, typically when they are first starting to lay. It's just one of those things. The shell simply forms around two yolks instead of one. There is nothing wrong with the hens. And no, the hens don't get into trouble for laying unusual eggs! Check out this video for more info on double yolks!

Double-yolkers are perfectly fine to eat and to use for cooking or baking.

With one word of caution! If you use them in baking (e.g. a cake, muffins or cookies), their additional volume may affect the outcome of the recipe.

Double-yolk eggs are sometimes sold with a label that advises they have an extra yolk, but often they are simply packed with other eggs that fall within the same weight range.

So how do graders know if the eggs contain two yolks without cracking the eggs open? Part of the grading process eggs go through before they reach the grocery store includes an inspection known as candling. The eggs are passed over a bright light that illuminates the interior of the egg. The graders check the size of the air space at the wide end of the egg (the smaller this space the fresher the egg), and they look for cracks in the shell, blood spots, any abnormalities in the egg - and double yolks!

If you find a surprise double-yolk egg or two in your carton, just consider it your lucky day!