Once we had a double yoke egg to hatch. The chick had 2 heads and 4 legs. Only lived a very short while.

I usually buy jumbo eggs and there are times that maybe 8 out of the dozen are double yolks. Not at all unusual.

A chook is another name for a chicken, Australian and New Zealand word.
Sharon

We always buy jumbo eggs & every dozen it seems has several double yolks in it. My DH says it is a sign it is going to be a great day!

Until a pullet (young hen) gets into a rhythm of laying eggs, she will lay some oddities. I've had some with no yolk, they are usually smaller. In a couple of weeks, the pullets will calm down and lay nice normal eggs. Younger chickens lay smaller eggs, and older ones lay larger eggs. But that is not to say that a young pullet will lay a very large double yolked egg. Did you cook it, sunny side up, and serve it?

I buy jumbo eggs at Trader Joe's and I average about 3 double yolk eggs per dozen

We always used ground oyster shell for calcium grit. Cleaner than used shells, since the bacteria was already baked out.

Oh, my!
I've never hatched any of my double-yolkers. Interesting.

We used to get them often, usually with hens that were beginning to lay. also got what dad called "pullet eggs" that were small, about 1/2 size.

Pullet eggs are from young hens. These are the first eggs they lay: very small. That's why the jumbo eggs usually come from older hens. I was amazed to hear what the double-yolk egg looked like when it hatched.