As a chicken owner, you may have cracked open an egg one day and been surprised to find not one, but two egg yolks inside. While abnormal, these “double yolk” eggs can occur naturally. But what causes a chicken to lay double yolk eggs, and are particular chicken breeds more likely to produce them? Let’s take a closer look.
What Is a Double Yolk Egg?
A double yolk egg is simply an egg that contains two yolks instead of one. The yolks may be fused together or separate. Visually, these eggs tend to be larger than normal. But besides having two yolks, the eggs appear normal.
Double yolks occur when a hen’s ovary releases two yolks into the oviduct instead of one yolk Both yolks are then surrounded by egg whites and one shell, forming a double yolk egg.
While unusual double yolk eggs are still edible and safe to eat. Some people even prefer double yolk eggs for baking and cooking since they provide extra richness!
What Causes Double Yolk Eggs?
So what causes a double yolk egg in the first place? There are a few potential reasons:
-
Age of the hen: Younger hens that have just reached laying age are more likely to produce double yolk eggs. Their reproductive systems are still developing, so releasing two yolks at once happens more frequently. As the hen matures, double yolks become rarer.
-
Genetics: Some chicken breeds genetically have a higher predisposition for double yolk eggs. Production breeds that lay very frequently like Leghorns seem especially prone.
-
Diet: A diet very high in protein can cause a hen’s oviduct to release two yolks occasionally. Cutting back on protein levels typically resolves this.
-
Stress: Stress, whether from overcrowding, weather changes, or relocation, may trigger short-term double yolk production. It’s the hen’s body responding hormonally to the stressor.
In most cases, double yolks are a temporary phenomenon in a flock. Once a hen matures and adjusts to consistent feed and environment, double yolks usually taper off. They pose no long-term health issues to the hen.
What Chicken Breeds Lay Double Yolk Eggs?
While any chicken breed can produce the occasional double yolk egg, some breeds demonstrate a higher tendency:
-
Production breeds – Common egg laying hybrids, Leghorns, and Rhode Island Reds are most likely to lay double yolkers. Their genetics promote very frequent egg laying.
-
Heritage breeds – Breeds like Australorps, Orpingtons, Plymouth Rocks, and Wyandottes may also lay more double yolk eggs in their youth.
-
Dual purpose breeds – Breeds that produce both meat and eggs, like Ameraucanas, Brahmas, and Cochins seem somewhat prone to double yolks.
Again, age is a big factor no matter the breed. Younger hens that recently began laying are more likely to produce doubles than older, established layers.
Tips for Getting Double Yolk Eggs
If you love baking with double yolk eggs, here are some tips to potentially get more from your home flock:
-
Raise pullets – Purchase day-old chicks or hatch eggs yourself so you know the exact age of your chickens. Young pullets within their first few weeks of laying are prime candidates for double yolks.
-
Choose production breeds – Breeds genetically wired for prolific egg laying like Leghorns and Rhode Island Reds produce more doubles, especially as pullets.
-
Provide a protein-rich diet – Feed younger hens a 16-18% protein laying ration to encourage a slight uptick in double yolks. Gradually reduce protein levels as they mature.
-
Reduce stressors – Minimize crowding, abrupt environment changes, and relocation which can stress hens and alter egg production.
-
Collect eggs frequently – Gather eggs 2-3 times per day so you don’t miss out on any double yolkers. The increased egg size makes them more prone to cracking.
With a little strategic planning, you can enjoy those delicious double yolk eggs from your backyard flock! Just remember double yolks are usually temporary in hens – a sign of their reproductive system maturing. So enjoy them while you can! With proper diet and care, your chickens should return to normal single yolk eggs as they grow up.
What’s the Chance of Finding a Double Yolk Egg?
If you start raising your own backyard flock, chances are youll collect your share of double yolk eggs. Its estimately that roughly one in every thousand eggs (about .1%) is double-yolked.
But in nearly five years of raising backyard chickens, and collecting hundreds upon hundreds of eggs, Ive only seen a handful of double-yolkers.
However, I recently was contacted by New Age composer Alex Shapiro who told me that she just collected a whole carton of eggs that contained 10 double yolkers! What are the chances of that?
Will Double Yolk Eggs Hatch into Twins?
Double-yolk eggs generally wont hatch if incubated, and if they do, both chicks usually dont survive, although its possible.
Hens who lay large or double-yolked eggs are more prone to becoming egg bound or suffering vent prolapse, both potentially fatal afflictions.
I admit that I am a bit worried about Annie.
Her regular eggs are huge, weighing about 2.6 ounces, but now that shes started laying gigantic double-yolk eggs on occasion, theres a far better chance she will get egg bound or an egg will break inside her, causing peritonitis.
But theres not much I can do but keep a very close eye on her for any signs of distress and be sure she doesnt get overweight, which can also lead to egg binding.
As you can see from the standard egg size chart above, even Annies normal 2.6 ounce eggs are considered to be in the jumbo category – and her 4 ounce eggs are off the charts!
DOUBLE YOLK EGGS – Why Chicken Laid Double Yolked Egg
FAQ
What breed of chicken lays a double yolk egg?
Any breed can lay a double yolked egg, but it may be more common from breeds that are good layers, like Rhode Island Reds, Sussex, and Leghorns. Double yolkers are a favorite for over easy eggs!
Why can’t double yolk eggs be sold?
Many poultry farms remove double-yolk eggs and don’t sell them because health-conscious consumers have become more averse to cholesterol-packed foods. As a result, some farms actually package double-yolk eggs and sell them separately.
How rare is a double yolk chicken egg?
Eggs with two yolks are fairly rare: statistically speaking, you might find them in just 1 of every 1,000 eggs. These eggs typically come from two types of hens: younger hens whose bodies are still just learning how to lay, and older birds who are experiencing the natural course of reproductive changes as they age.
What breeds of chickens have double yolks?
However, double yolks can be hereditary in chickens, with some breeds tending toward them in the same way that twins might run in a human family. You are more likely to find them in breeds that are considered good layers such as Rhode Island Reds, ISA Browns and Plymouth Rocks.