Are you wondering, why do chickens lay double yolk eggs? Cracking open an egg to find a double-yolk is rare, but it’s always a nice surprise and believed to bring good luck. In this article, I’m explaining why and how often hens lay double yolk eggs.
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Why Do Chickens Lay Double Yolk Eggs?
The reason why chickens, and more specifically hens, lay double yolks is simply that sometimes they release two yolks when they start the process of creating an egg.
Let’s be real here, how eggs are produced is nothing short of a miracle.
To explain the process, however, it’s pretty straightforward. Hens have thousands of tiny ‘ova’ in their ovaries, and these are what become yolks during the process.
When they start a cycle and are producing an egg, a hen’s body releases a yolk from the ovary into their oviduct.
From there the yolk travels through the oviduct and the rest of their reproductive system as the rest of the egg is created.
With a double yolk egg, the only difference is that two yolks were released at the start of the process.
As to the ‘why’ this happens, that is not exactly known. What we do know is that double yolks are much more common with young hens that have just started laying.
This is believed to be because their reproductive systems are not fully mature.
It’s also more likely with older hens that are close to the end of their laying days. Again, this is probably to do with changes in their reproductive system.
Double yolks are very rare from hens in their egg-laying prime. Overall, the odds are around 1 in 1,000, so that gives you an idea of just how rare it is to find a double yolk.
Related - Is it safe to eat double yolk eggs?
How Do I Get My Chickens to Lay Double Yolk Eggs?
You can’t do anything to make your chickens more likely to lay double yolks, it’s just something that has to happen naturally.
As I explained, it is more likely in younger hens that have just started laying. I’ve also read a lot of accounts from backyard chicken owners that say prolific laying breeds like Rhode Island Reds, Leghorns, and the Sussex are more likely to produce doubles.
This may just notice this as these breeds lay more eggs though, it’s hard to say.
If you find a double yolker, you really do just have to consider yourself lucky. The fact that it is so rare is why a lot of people do associate finding one with good luck.
What Kind of Chicken Lays a Double Yolk Egg?
This is often debated by owners that get double yolks from their chickens. However, it’s generally agreed that there are no breeds of chickens that are more likely to lay double yolk eggs over others.
It’s believed that good egg-laying breeds are more likely, but as I mentioned, this may be just down to the fact that they lay a lot more eggs.
If you love a double yolk and you’re trying to find your own little double yolk producing machine, unfortunately, it’s just not possible.
How Rare Is a Double Yolk Egg?
Overall, it’s estimated that finding a double yolk is a 1 in a thousand chance. You can increase those odds by cracking open eggs from young hens, of course, or even cheat by buying double yolk eggs!
Can You Buy a Carton of Double Yolk Eggs?
You can buy cartons of double yolk eggs, yes. It’s possible to tell if an egg has more than one yolk in by candling it.
Candling is the process of pressing a light onto the side of an egg so you can see what’s inside based on the shadows.
This process is commonly used to check embryos are developing properly inside an egg, but it can also be used to see if there is more than one yolk.
Some egg farms will put all of their double (or even more than double) yolk eggs to one side then sell them separately.
It’s worth checking in your local supermarket if they sell these. Or even better with a local farmer’s market or hatchery if you have either of these near you.
Will a Double Yolk Egg Hatch Twins?
It’s possible for a double yolk egg to produce two chicks, which you can call twins, yes.
It is the yolks that become the chicks, and the white of the egg provides nutrition to the growing embryo.
There are some complications involved with hatching twins though. First of all, the yolks need to be fertilized.
Almost all shop-bought eggs are not fertilized. For an egg to be fertilized there needs to be a rooster present in the flock, and he needs to have mated with the hen that laid the egg within a time period before she produced the egg.
Then the process of two chicks developing inside the same egg is a tricky one to say the least.
One embryo will often out-compete with the other. Taking more of the nutrition from the egg white and stopping the full development of the other.
Then there is the issue of space. An eggshell is designed to be just the right size for one chick, having two in there can cause some problems.
I know that a lot of people incubating eggs have had to step in when the chicks were hatching age and help crack them out of the shell.
There just isn’t enough room for them to move freely and ‘pip’ the eggshell with their egg tooth and start to chip their way out.
Related - How long is a chicken gestation period?
In Summary
I hope this article has helped clear up all the questions you have around why chickens lay double yolk eggs, as well as what it means, how it happens, and just how rare it is to crack open a double yolk.
If you’re on the hunt for a double yolk egg or even a triple yolk which is ever rarer good luck!
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Image credits - Photo by Nick Fewings on Unsplash
