How to tell if chicken eggs are fertile? (1 classic method)

In this brief guide, we will answer the question, ‘ How to tell if chicken eggs are fertile?’. We will look at the methods that can help us to determine if a chicken egg is fertile. We will also look at the common biological aspects associated with a fertile egg.

How to tell if an egg is fertile?

A fertile egg has a small white circle on the yolk. The circular shape denotes a cluster made of fertilized cells that could potentially develop into a baby chick.

How does the candling method help to determine if an egg is fertile?

The candling method follows after you incubate the egg for a few days.

After you have incubated the eggs, go to a dark room, and shine light at the wide end of your egg. The light will help you to see a dark patch at the middle of the egg that has a network of veins around it or if it appears opaque.

If you don’t see the veins and spot the egg yolk instead, it means that the egg is not fertile.

The candling is an acceptable method to keep track of the stages of the incubation process. 

How does a hen’s egg become fertile?

A hen will lay eggs whether or not she has ever mated. After the hen matures at six months of age, she will start to lay eggs almost every day. The hens have an ovary and an oviduct. The ovary is responsible for the development of the egg. A hen will lay an egg every day which, is as long as it takes for the egg to form fully in her reproductive tract. 

The egg formation starts in the ovary which, then transfers into the oviduct. The sperm infuses into the yolk; hence the egg produced is fertile. In the absence of sperm, fertilization does not take place. Instead, the egg travels further along the oviduct, where the yolk gets enclosed in egg white, followed by the inner and outer shell. The egg leaves the oviduct and enters the uterus, where the outermost hard shell forms. The fully-formed egg then exits through the vagina and out from the cloaca.  

A chicken egg can be either fertile or infertile. An egg is probably fertile if the hen had mated with a rooster before laying the egg. The sperms from the rooster will travel through the hen’s oviduct during copulation.  The sperm will then fertilize the yolk of the hen’s egg. Sperms remain inside the reproductive tract of the hen for up to a couple of weeks until fertilization. The sperm takes over a week to fertilize the egg as it travels to the oviduct. It is interesting to note that the eggs lain by the hen will continue to be fertile for two to three weeks after mating. 

A fertile egg has the genetic material of both the rooster and the hen. A fertile egg or an embryo is possible to identify. The fertile egg exists as a white speck in the yolk that is called blastoderm. The blastoderm will develop into an embryo; only if stored at 85 Fahrenheit for a day.

A fertile egg needs to be incubated to birth a chick. Otherwise, it will not. The store-bought eggs, raised for consumers, are usually infertile. Fertile eggs, however, are safe to eat unless; incubated. After 3-4 days of incubation, a fertile egg starts to form a chick. 

The embryo in a fertile egg is only a minute blemish on the yolk that stops growing after the egg sets down in a refrigerator. 

However, if an egg is fertile, it does not mean that it will hatch a chick. You can identify if your egg is fertile if you spot a blemish on the yolk.

Even after candling, there is a chance to err the fertility status of an egg. For a definite answer, you need to crack open the egg. 

Before you proceed with the incubation process, you need to make use of probability. Crack open a few of the eggs from the batch to determine if most of them are fertile. Even if you lose a few eggs to perform the test, it will save you disappointment afterward.

 If you crack some of the eggs and find most of them to be fertile, you can put them in an incubator where they will hatch into a chicken. Not every one of the fertile eggs will hatch a chick but, the chance of hatching will be higher. 

After the eggs have incubated, the cells or the white spot on the yolk will divide and form an embryo. 

In this brief guide, we answered the question, ‘ How to tell if chicken eggs are fertile?’. We looked at the methods that can help us to determine if chicken eggs are fertile. We also looked at the common biological aspects associated with a fertile egg.



Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.

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