Why do Chickens lay eggs?

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Why go through the whole egg and hatching problem?

Procreation: Laying eggs is how chickens would naturally produce the next generation and is purely for reproduction from the chickens point of view. We have adapted and controlled their natural behaviour to service our society, a bit like the Borg in star trek.



From the human point of view we find it useful to select birds which lay the most eggs in the shortest time and it is artificial selection and or selective breeding that produces the chickens we know today that seem to lay and egg a day. The hen has no idea she is, in the vast majority of cases, laying an unfertilised egg.

We have just adapted the normal behaviour of the wild chicken and used it to our advantage.

All it takes is a farmer choosing the hen that lays the most eggs as the progenitor for the next generation. Perhaps without realising it, humans have been genetic bio-engineers ever since the dawn of agriculture through selective breeding. After many generations over the thousands of years that chickens have been domesticated they have laid more and more eggs per year as a result of humans selecting for this trait.

Why do chickens lay eggs and not chicks?


This is a bulk processing solution to raising a family. Laying a clutch of eggs, incubating and hatching them is a sure fire way of producing a dozen or so chicks at the same time.

This way they are all at the same stage of development at the same time. It is also a test to ensure the chicks are strong enough, Hatching is quite an intense process and weak chicks will not survive, this ensures survival of the fittest.

If a chicken laid or produced a live chick instead of an egg she would only be able to have 3 or 4 babies a year. It takes 21 days to grow a baby chick so even if she had them in quick succession with a long breeding season she would struggle to maintain the flock.

Also if chickens produced live young they would all be a different stages of development and this really does not work as bigger chicks bully little ones all the time.

Will chickens lay eggs year round?


They can do. A few years ago I hatched a batch of hybrids called an Amber Stars and the hens from that group layed a large egg every day for nearly 2 years before they started to decline. And this was quite far North in Yorkshire. The normal egg cycle of the wild hen has been disrupted by gradually breeding out the effect of the genes that link egg laying cycle to light and seasons.

Commercially chickens are kept with extra hours of artificial light to keep them laying. This is to ensure profitability and continuity of supply chain. An egg business depends on regular production so hens are brought in ready to lay and kept in artificially long days for 80 weeks before being cleared out.

Do chickens lay eggs their whole life?


Chickens lay eggs for most of their lives. they start between 16 and 30 weeks ,depending on the breed, and may lay for 6 or 7 years before finally stopping.

A chickens will lay around 800 eggs in it's life. If it is a hybrid it will lay those more or less continuously over 3 years and then stop. If it is a heritage or rare breed it will take 6 or 7 years to lay that many eggs and then stop.

Chickens don't die because they stop laying eggs, I have had some live to 11 years quite happily.

Hybrid chickens tend to lay eggs until they die, they have been bred to live fast and die young and the bodies cannot cope with that level of egg production for long. Heritage chickens do for the most part lay eggs all their lives but they lay less and less over the years. I have a few seven year old birds and they still produce a handful of eggs in the spring, around 20 or so.

I can only discuss trends and tendencies when it comes to how many and how long chickens lay eggs for as they are always individuals that buck the trend.

Commercially produced shop bought eggs come from chickens that are less than 80 weeks old. When they reach 80 weeks they are disposed of and new ones bought in to replace them. This is because they are no longer profitable after that as egg numbers and egg quality begins to decline with age.

Does it hurt chickens to lay eggs?


And does it take time for them to get used to it? I have no way of knowing absolutely but I would say it does not. I have around 300 chickens and have seen a great many of them laying eggs over the decades and they seem very content when settled on a nest to lay.

It does take them a little while to settle into eggs laying and get used to it. The odd pullet produces eggs with blood streaks on when they first start so it's not without it's problems.

I've never heard one make any sort of noise that would indicate that they were in pain while laying an egg. After the egg Is laid, however, they will often squawk loudly.

The reverse is true and if they can't lay an egg it is very uncomfortable and distressing. The inability to pass an egg is called egg binding and it’s lethal to a hen. I’ve been blessed that so far in that I see this issue very rarely.

Below: This is a series of images with a goose laying an egg.

I had to move a flock recently and three hens who needed to lay were not able to. They had their beaks open and were panting and constantly moaning in a long load squawk they don’t usually use, signs of severe stress and pain. They do like a quiet and undisturbed spot for nest and disruption will cause them to hang onto an egg.

You will be pleased to know they settled straight back in in the new coop and produced their eggs in a few minutes.

If the egg is too large, chickens can prolapse, which means their insides pop out. There are a great many reasons for this, inadequate diet, the egg may not develop properly, Thin shelled or shell less eggs or the hen’s muscles may not be strong enough to push an egg out.

They can become egg bound and if the egg breaks inside of them, they often die. If the problem isn’t recognised, a second egg will collect inside and cause severe stress. Surgical intervention is then needed but it’s rarely successful.

Battery farm chickens that have been rescued from egg laying factories are often given regular injections or implants to stop the egg laying.

Birds are designed to lay eggs and after the first few are quite used to the process.

Do all chickens lay eggs?


For the most part all female chickens do lay eggs. There are a few conditions where a damaged ovary means they do not. Provided they are well fed and looked after they should lay normally.

Can chickens lay eggs twice a day?


Chickens certainly can lay two eggs a day, I have seen it myself on several occasions.

It is rare and even with over 300 chickens I only see it occasionally. It only happens in young birds at the peak of spring and sometimes two yolks are released into the oviduct in the same day. This results in two egg being laid the following day a couple of hours apart.

This often confounds backyard chicken keepers as they spend a lot of time wondering how they got 7 eggs in the nest one day and they only have 6 hens.