One of my girls had a surprise for me

I found a ginormous egg in one of my nest boxes. One of my girls is defiantly putting fourth that special effort. I suspect that one of my Buff Orpington are laying this gorgeous egg, they are the larger of my girls, but I could be wrong. If I'm able to find out which hen is responsible, I defiantly owe her a special treat, maybe a weeks worth of special treats. This egg measured three inches long. Looks more like a duck or goose egg.

Can't close the top on the carton