This egg is easily twice as big as any egg we have gotten from our chickens. I placed it in a jumbo size egg carton and couldn't close the container. A whopper of an egg - I think the culprit is Yoko our Rhode Island Red. She lays the biggest eggs on a regular basis.
Our second surprise was when we cooked the egg. It appears the reason for this huge size is a double yolk. Essentially we got two eggs in one. :) Thanks Yoko.