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Why Do Chickens Lay Unfertilized Eggs?

Nicole Cosgrove

May 24, 2021

One of the most mysterious things about chickens is that they continue to lay eggs even if there are no roosters around to fertilize them. In most other animal species, including the prolific rabbit, eggs are only laid once a male fertilizes them. However, the chicken can lay an egg almost every day whether there is a rooster present or not. Keep reading while we take a closer look at this strange behavior and discuss the difference between fertilized and unfertilized eggs, how many eggs are in a clutch, how many eggs a chicken can lay, and more to help you learn more about your flock.

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Why Do Chickens Keep Laying Eggs?

chickens_Peter Turner Photography, Shutterstock
Image Credit: Peter Turner Photography, Shutterstock

While no one has been able to get into a chicken’s mind to tell us why they lay so many eggs, we do know what they are trying to accomplish. Some chickens can almost compulsively lay a clutch of eggs and sit on them. Sitting on the eggs is called brooding, and poultry farmers prefer chickens that don’t brood and instead get up and leave the eggs, so they are easier to collect. Chickens will return to the same nest each day to lay an egg until it has a clutch, which is about a dozen eggs. Once it has a clutch of eggs, it will stop laying them and be happy brooding.

However, if the farmer collects the eggs every day, the chicken will never have a clutch of eggs and will continue to lay them in pursuit of that goal.

Fertilized Versus Unfertilized Eggs

chickens in farm_ piqsels
Image Credit: Piqsels

When a chicken mates with a rooster, it will produce fertile eggs for the next week. These fertile eggs will hatch if kept in the correct conditions, but if the poultry farmer collects the eggs every day and keeps them refrigerated, they will be nearly indistinguishable from unfertilized eggs in appearance and flavor. Besides the eggs being fertile and the chicken having mated, there will be no difference in the chicken’s routine, and if there were half a clutch of unfertilized eggs in the nest, the chicken would be happy to add the fertilized egg to the collection.

Signs Of a Fertilized Egg

chicken eggs_Couleur_Pixabay
Image Credit: Couleur, Pixabay

Fertilized eggs kept at about 100 degrees in 60% humidity for several hours will begin to transform into a baby chicken, and the first signs will be a veiny structure inside the egg. It will take 3-4 days for the veiny systems to appear and approximately 3 weeks for a chicken to hatch.

How Many Eggs Can a Chicken Lay?

 Chicken hen_JACLOU-DL, Pixabay
Image Credit: JACLOU-DL, Pixabay

Chickens, like humans, are born with a set number of eggs that they can lay. If your chicken runs out of eggs, it will stop laying them, but most chickens will stop laying them due to old age instead. A chicken can have more than 15,000 eggs at birth but will usually only lay 100 to 300 eggs per year for 3-4 years. The average chicken likely produces about 600 eggs in total, but it can vary significantly from one breed to the next, and there are hundreds of breeds.

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Summary

It seems that chickens are more interested in obtaining a clutch of eggs than anything else and don’t seem to notice if they have mated with a rooster or humans keep stealing their eggs. As long as their nest has less than a dozen eggs, they will sit there laying another more eggs for the next 3-4 years. You can eat fertilized and unfertilized eggs as long as you collect them every day and keep them in a refrigerator. At an average of 600 eggs per chicken, you get quite a bit from a single animal without much effort on your part.

We hope you have enjoyed reading over this guide and found it helpful for answering your questions. If you have learned something new, please share our answer to why chickens lay unfertilized eggs on Facebook and Twitter.


Featured Image Credit: thieury, Shutterstock

Nicole Cosgrove

Nicole is the proud mom of Baby, a Burmese cat and Rosa, a New Zealand Huntaway. A Canadian expat, Nicole now lives on a lush forest property with her Kiwi husband in New Zealand. She has a strong love for all animals of all shapes and sizes (and particularly loves a good interspecies friendship) and wants to share her animal knowledge and other experts' knowledge with pet lovers across the globe.