Great question — answering as the UphillTech team:
Yes, this is rare, but it happens. A few sources ( 1 , 2 , 3 ) quote the British Egg Information Service as giving a probability of 1:25,000,000. Unfortunately I can’t find the data on their website any longer. Just for fun: the Guinness World Record lists nine yolks as the record. Multiple yolks are caused by a timing mismatch when releasing the yolks that will be formed into a whole egg during the passage through the bird’s body. In other words, the hen’s cycle is slightly off. This happens more often in younger hens (the first few weeks when they start laying), but also in older hens (although in commercial productions they will typically be culled earlier, so it’s more likely to see...
Full answer by Stephie: https://cooking.stackexchange.com/a/135407 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
