When I was growing up my grandma had a hen that laid a double yolk egg every time. Grandma said she thought it was because she only laid every 4 days. That was the only hen she kept out of the stew pot and let grow to old age. I asked why just her and she said any hen who could do that was like the Golden Goose of all egg layers!
We like to make our double yolk eggs into deviled eggs......they just look TOO cool!!! We get most of ours from our Red SexLink....I think the sex link chickens do more of the mondo eggs.