Ok this is truly mundane and pointless.
I was making a egg-potato-suasage dish for brunch this morning and one of the eggs had a double yolk.
I’ve heard they aren’t all that rare, but this is the 1st one I’ve seen. Or if I’ve seen another it was > 10 years ago. Not that I go through a lot of eggs (other than the summer i worked as a prep cook, and would go through 96 eggs at a time making hollandaise sauce)
Brian
When I was getting my eggs from a friend with chickens we got lots of double yolks. Probably ¼ of the eggs were double yolked. I never saw them when I had store bought eggs, though.
I don’t know what is the answer to the implied question, but I once bought a dozen eggs that all had double yolks.
Once when I was working as a line cook I got an entire flat of 30 eggs that were all double yolks.
So did Kalhoun! Sounds like someone just put the wrong carton on the “to be sold” pile when it should have gone on the “to the bakery” cart.
A guest named **feebee **had the same thing happen and in that thread I shared how I had a fertile double-yolk egg in grade school when we studied embryology. Sadly, both chicks died, although the both developed much further than my teacher said they would.
Also, Harmonious Discord said that some chickens lay nothing but double yolked eggs, but that most of them never make it to the supermarket. If you buy your eggs from a farmer like her family did, you’d see a lot of weird eggs - even a triple yolk!
Me too. 
Store bought.
I have seen dozens of them.
I see them all the time…I don’t go through ALOT of eggs, but it seems to me that out of every dozen I buy, say once every month or more, there are 1 or 2.
According to the other threads, double yolked eggs are separated out during the packaging process. To me it almost seems MORE likely tha you would get an entire dozen double yolked eggs than one (out of 10, couldn’t tell with the remaining 2). The egg wasn’t obviously bigger (these are size large) But it would have to be significantly bigger, because I probably didn’t even really look at the egg before breaking it.
Brian
A long time ago, as a mere boy, I raised chickens. They tended to lay a fair number of double- (and occasionally triple-) yolk eggs when getting started as layers. The proportion always seemed to decline after several weeks.
Presumably, consumers tend to regard these as weird and possibly dangerous, so serious egg producers have methods designed to screen out multiple-yolk eggs. Sometimes, these methods fail.
We see lots of them but that’s probably because we have around a hundred or so chickens and have farm fresh eggs every day. Some times we sell eggs to nieghbours and their friends when we get too many. The thing that really amazes me is when people complain that our eggs are bad because the yolks are a rich golden colour rather than the almost pale store brought variety.
When I was a kid, we used to get our chickens and eggs from a local farm. Double yolks were fairly common, and I remember a few triple yolks as well.
I don’t go through a lot of eggs, but I honestly cannot remember the last time I’ve seen a double yolk. Certainly not common around here in supermarket eggs.
It’s not surprising to see double yolks among the store-bought Jumbo cartons here. Sometimes I know before I break it that an egg will have a double yolk.
Once I cracked two double-yolked eggs in a row - I took it as a good luck sign! 
That’s too funny! But, I have to admit said the city girl, when I cracked open my first fresh, honest-to-goodness free range organic fed hen’s egg, I was a little put off by the orange yolk. Once I tasted it, though, that went out the window. Who knew eggs are supposed to taste buttery all on their own? 
I lived on a farm in Ireland for a while and the received wisdom there was that double yolks come from old hens.
In the latest issue of Mother Eart News ( April/may 2007) there is an article about keeping chickens and the Store Bought-warehouse produced -inhumane conditions for chickens eggs vs Free Range/Cage Free/ Free Roaming */Farm raised chicken eggs.
The farm raised eggs had similar levels of fat to the production eggs, but the farm raised ones had nearly three times the omega-3 fats and 62% higher vitamin a and 220 percent higher Vitamin E. They also contain higher levels of carotenioids like lutein and zeaxanith, which are thought to be important to eye health.
If you want to try farm fresh eggs:
Local Harvest Eat Wild
Eat Well Guide and put in your zip code to find the closest chicken (or farmer) to you.
*Cage free, Free Range or Free Roaming terms seen on the egg cartons at the local supermarkets are currently regulated by the US Gov’t, though there may be some third-party verification and programs.
Free range usually means the laying hens are raised in large flocks in a big open warehouses rather than stacked cages ( which are 67 square inches in size or the size of two thirds of a sheet of paper) They can walk around and flap their wings and preen their feathers a little.
Cage Free does not mean outdoor access.
Free Range implies some outdoor access, although very limited and on dirt or concrete, rather than pasture.
The chicken industry can warehouse up to 100,000 birds in a single building in cages that are as spacious as two thirds of a sheet of paper. The crowded conditions lead to cannilbalism and other destructive behavior, so the birds beaks are cut off at an early age. They are kept in a windowless warehouse with prolonged artificial light to stimulate maximum egg laying. When egg production drops off, food is withhedl as a way of sending birds into a forced molt before another round of egg laying before being disposed of. .
For these above reasons are why the increased risk of salmonella in eating undercooked eggs or raw cookie dough mmmmmmmm raw cookie dough.
For a really good read, pick up this month’s issue and turn to page 72.
That said, I’ve never seen a double yolk and I cannot tell you how badly I would love too.
I lived in A’dam last year for a few months. You can buy packs of double yoke eggs there. Extra yoke is always good.
I just finished another dozen last week that was 8 out of 12 doubles! Each time I opened one I ran into the living room with the bowl to show Mr. K! He was underwhelmed, but I was absolutely over the moon!
If you go for the “jumbo” size, your chances of doubles are greater than if you go for plain ol’ “large.”