From you question it is a bit more common than most people think. I had a friend who raised chickens. He gave me a dozen eggs and 10 of them were double-yolked.
They would always be a large egg....I think we have maybe gotten 3 double in a lifetime of store bought eggs. I don't think they would reject a double.
Thank you. I know we are getting a better rate than the 1/1000. Ours have only been laying for a couple months. We probably have only gotten about 300 total and have had roughly two dozen double yokes. It may even out as they get older....
I'd have expected it be similar to the probability of identical twins. However within batches the probabilities are not independent.
This post was edited by Malizz at October 19, 2018 4:03 PM MDT