I never understood why normal egg producers work so hard to prevent selling a double yolk. Whenever I get a double yolk, I feel like I got a prize. One time I bought eggs at Natural Grocers and 8 out of 12 eggs had double yolks. Score!
Discussion
similarly to that, bigger eggs tend to be frome more mature chooks, those don't have double yolks so often but their larger mass mostly compensates for that