About seven or eight years ago, out of one box of 12 eggs, I had double yolks three days in a row and another double yolk on the fifth day. Never happened before nor since. Quite amazing. I probably should’ve bought lottery tickets.
Until recently, we had about 150 chickens, getting about 70 eggs a day.
We’d get at least one, sometimes two doubles a day. They’re pretty common.
I did get a triple once.