Subscribe

Friday, September 20, 2013

Double Yolkers - What Causes a Double-Yolk Chicken Egg?

~Annie's double yolk egg (on the left) compared to her normal-sized eggs~
by Lisa at Fresh Eggs Daily

Annie, one of our Australorps, has always been a big girl who lays big eggs. So when she laid a whopping 4.2 ounce egg one day last week, I wasn't all that surprised.  It turned out to be a double-yolker. Then yesterday she laid another giant 4.1 ounce egg, that dwarfed even our duck eggs. It was also a double-yolker. So I decided it was time to share what I know about double-yolk eggs.

Roughly one in every thousand eggs (about .1%) is double-yolked.  Since commercially-sold eggs in the United States are sold by weight and also candled prior to packaging, any double-yolkers are discarded (although in the UK they are not) and you could go an entire lifetime eating store bought eggs and never encounter one.  But start raising your own backyard flock and chances are you'll collect your share. But in nearly five years of raising backyard chickens, and collecting hundreds upon hundreds of eggs, we've only seen a handful of double-yolkers. 

~Annie's huge 4.2 ounce double yolker next to two regular chicken eggs~
So what causes them?

A double-yolked egg occurs when two egg yolks are released into a hen's oviduct too close together and end up encased within the same shell.  Generally about an hour after an egg is laid, the next yolk is released, but due to hormonal change/imbalance, an overstimulated ovary sometimes misfires and releases the yolk too early.  The shell forms around both yolks and results in a single egg. 

~Annie is far larger than our other Australorps~
It's far more common to find double-yolked eggs from new layers or those hens on the tail end of their laying life.  It can be genetic, and therefore hereditary, and is more common in the hybrids and heavier breeds.  In Hong Kong and India, chickens are actually bred to lay double-yolked eggs that are highly sought after by customers.

Double-yolked eggs generally won't hatch if incubated, and if they do, both chicks usually don't survive, although it's possible.  Hens who lay large or double-yolked eggs are more prone to becoming egg bound or suffering vent prolapse, both potentially fatal afflictions.

~a 'regular' Annie egg next to a medium-sized chicken egg~
I admit that I am a bit worried about Annie. Her regular eggs are huge, weighing about 2.6 ounces, but now that she's started laying gigantic double-yolk eggs on occasion, there's a far better chance she will get egg bound or an egg will break inside her, causing peritonitis. But there's not much I can do but keep a very close eye on her for any signs of distress and be sure she doesn't get overweight, which can also lead to egg binding.

~Egg weights for standard US size grading~
As you can see from the standard egg size chart above, even Annie's normal 2.6 ounce eggs are considered to be in the jumbo category - and her 4 ounce eggs are off the charts! She's our best layer and I save her eggs to make fried egg sandwiches for breakfast usually on Sundays. Our smaller eggs I use for scrambling.

~Cracking the first gigantic egg to see if it was a double yolk egg~
~And it was~
If you've never seen a double-yolk egg, you might be interested in watching this short video clip I made:


Annie is three years old, so well into her productive laying life, but hopefully with a few more years of good laying ahead of her. She has the tendency to go broody, and was a great mother to a clutch of chicks this past spring, so either way - as all our hens do - she has a home here with us for a long as she likes.

~Annie raising a clutch of chicks she hatched this past spring~


BECAUSE LIFE IS JUST BETTER WITH CHICKENS!


 photo ChickFB_zps883649b9.png photo ChickTwit2_zps38ed4e1d.png photo ChickInstagram_zps8fd24aee.png photo ChickPin_zps1879a45a.png photo ChickYouTube_zpse8aa0682.png photo ChickBlogLove_zps1436ce44.png photo ChickGoogle_zpsfb14edcf.png
©2013 Fresh Eggs Daily, Inc. All rights reserved.

22 comments:

  1. That's very interesting. One of our girls was laying double yolked eggs a few weeks back but I don't know which one. However, one of the hens stopped laying, and for a few days had what looked like egg all over her backside. Now she is not laying at all. She seems health and is eating well. Do you have any idea what could be wrong?

    ReplyDelete
    Replies
    1. Is she molting? That would be my guess. Otherwise her hormones seem to be going haywire for some reason. I would think maybe an egg broke inside her but if she seems okay and is eating and drinking and running around, I guess it didn't end up infected or to cause her peritonitis. Keep a close eye on her but I would guess she's now molting.

      Delete
  2. My silly Pekin duck lays a huge double yolker every other egg she lays. Then this week she laid two eggs in one day. I use the double yolkers to replace two extra large chicken eggs when I bake. Thanks for the info on why she is doing this - we all wondered.

    ReplyDelete
  3. I have only had a double yolk a couple of times. I can't imagine getting one 4.2 ounces! Thanks for all of the good info.

    ReplyDelete
  4. Thanks Lisa! So informative. I had no idea why this sometimes happens and why it is so rare! I always put it up there with getting 3 peanuts in my peanut shell at the ball game! :-) Rare but you are so excited when it happens.

    ReplyDelete
    Replies
    1. OMG! I totally know what you mean about the peanuts! I mean, its really no big deal but exciting all the same :0)

      Delete
  5. My Great Grandpa had chickens when I was growing up and I remember how excited I was when I would get a double yolk egg at their house. Fast forward lots of years of my eating store bought eggs until I finally got my own hens. I think I was just as excited when I got my first double yolk from my own girls as I was when I was little.

    ReplyDelete
  6. Thank you for the information. I got one in a regular size egg from a young chicken. It is scary though when you think about all that can happen to chickens. I get so attached to them. Just like we women, there is always a possibility of a problem.

    ReplyDelete
    Replies
    1. So true, its amazing how well their reproductive systems work...laying an egg nearly every day.

      Delete
  7. Double-yolkers are a treat. In the past year of having the girls...only one so far.
    Waiting for your book to arrive :-)

    ReplyDelete
  8. A few weeks ago I got some free-range eggs from a neighbourhood stand and 4 out of the 12 eggs had double yolks - and they weren't any larger than a normal large egg! So I'm surprised to hear that double yolkers are actually statistically so rare! At 4 out of 12, I was definitely beating the odds ;)

    ReplyDelete
  9. I have 3 hens and one Pekin duck that will lay double yolk eggs. I see an increase in the hens laying double yolkers after they eat a lot of protein like shrimp shells/heads and such. We live on the coast and when we get shrimp, we sit outside to head them and the chickens are like vultures after the shrimp. Someone told me not to feed them any kind of shellfish as it will make the eggs taste fishy but they were fine so I am not worried about that.
    I took a picture after cracking three eggs into the pan and had 6 yolks. I think I definitely beat the odds there.

    ReplyDelete
    Replies
    1. wow! 6 yolks, now that's something! Yes added protein can cause them. I feed ours shrimp shells too when we have them and they love them. I wouldn't worry, I've never had a fishy egg either!

      Delete
    2. I THOUGHT ONLY ONE YOLK DROP PER 24 HRS on double yolks either no egg day before or day after!!

      Delete
  10. We get our share of double yolkers but once we got a no-yolker and one pinto bean size egg. Why do they sometimes lay torpedo shaped eggs? Long and pointed on both ends!

    ReplyDelete
    Replies
    1. Just a glitch. It happens. Considering they lay an egg nearly every day, its surprising that more doesn't go wrong.

      Delete
  11. This comment has been removed by the author.

    ReplyDelete
  12. I found it interesting when you said that double yolkers are prone to egg binding and prolapse. I had HORRIBLE winter last year. We had new ISA brown layers and the size of the their eggs were enormous, and we got them everyday. We had prolapse like crazy. I tried everything, researched everywhere. But they kept dying. It was so sad. Then the others started picking and making the problem bigger. It was heartbreaking. I didn't know how to solve it. It was so bad that I'll never buy that breed again.

    ReplyDelete
    Replies
    1. Oh that's so sad. I think that sometimes the hybrids that are bred to be laying powerhouses don't live as long as the heritage breeds who might not lay quite as often.

      Delete
  13. I hardly ever saw them with my previous chickens which I got when they were already past their prime, but I had a few double yolks from my new chickens when they first started laying. Thanks for explaining that!

    ReplyDelete
  14. Thanks a lot for your great presentation, i am very interested to your sharing and all post are so nice
    Thanks for your awesome presentation...
    Logo erstellen

    ReplyDelete

Thank you for your kind comments and joining along with Fresh Eggs Daily as we live our wonderful, natural country farm life.

Lisa of Fresh Eggs Daily
www.facebook.com/FreshEggsDaily