4 Basic Phases to the Chicken Life Cycle

The United Nations estimates there may be as many as 23 billion chickens on this planet right now.

With less than 8 million of us, that means there are nearly three chickens for every one person!

Yet, factually speaking, we don’t really know all that much about the chicken life cycle. Yes, we know (or can infer) that chickens reproduce quickly – the numbers speak for themselves there!

We know that we eat a lot of chickens and a lot of chicken eggs. And we know that there are different breeds of chickens that can look quite different on the outside even though they are basically the same on the inside.

But what is the chicken life cycle? Does it have different parts? How long does it take a fertile chicken egg to hatch? How many years does an adult chicken live? Let’s explore these and other interesting questions about the chicken life cycle!

Chicken Life Cycle: An Overview

chicken life cycle

There are four basic phases to the chicken life cycle.

Phase 1: Embryo

The embryo phase starts the moment the egg gets laid. It takes 21 days for this phase of life.

Phase 2: Chick

The chick phase starts on day 21 when the chick hatches. The length of time it takes for this phase depends on the specific breed of chicken.

Phase 3: Pullet (Adolescent)

The pullet stage is often forgotten about when you think about chicken development. As it turns out, chickens are just like people in this way – they have to become teenagers before they become adults.

Phase 4: Adult

The adult chicken’s phase of life can last up to seven years. The lifespan of an adult chicken depends on breed and also on husbandry.

So now let’s look more closely at what happens during each of these four basic chicken life cycle stages.

Chicken Life Cycle As An Embryo

chicken egg cycle

Female chickens can lay two kinds of eggs: infertile and fertile. Only the fertile eggs will hatch and become baby chicks.

When a female chicken lays a clutch of fertile eggs, it takes approximately 21 days before the little chicks will start to emerge.

The moment the egg gets deposited into the nest, the action begins.

Day 1: Tissue begins to form and develop.

Day 2: The heart gets made and starts beating.

Day 3: The circulatory system begins forming and the chick’s tail bud appears.

Day 4: The little chick’s limbs begin to grow, including wing buds and leg buds. The brain and eyes also begin to form.

Day 5: The chick gets knee buds and elbow buds.

Day 6: Individual digits form for the chick’s toes and claws. The beak also starts to form.

Day 7: The beak continues to form and the egg tooth appears (what the chick uses to break out of the egg). The comb also starts developing.

Day 8: The little chick starts to grow feathers.

Day 9: The mouth opens up

Day 10: The chick’s claws start to form.

Day 11: Tail feathers begin to grow in.

Day 12: The feet and legs start to form scales.

Day 13: The chick gets eyelids.

Day 14: The chick’s body turns so the head is at the larger end of the egg.

Day 15: The chick’s gut is drawn in towards the abdominal area.

Day 16: Feathers cover the chick’s whole body.

Day 17: The chick’s head draws down between the legs.

Day 18: The chick’s body completely fills the interior space of the egg.

Day 19: Nearly the whole yolk sac is absorbed.

Day 20: The chick uses the egg tooth to start pipping (breaking through the egg shell) from the inside.

Day 21: The chick continues pipping and breaks out of the egg to hatch.

Isn’t it amazing that so much can happen in just 21 days!

This video explains in visual form exactly what happens on each day of the chicken life cycle inside the egg so you can see exactly how the chick looks each day of its development.

Chicken Life Cycle As A Chick

The chick stage of the chicken life cycle is the cutest, without a doubt. Chicks are adorable round puffs of feathery fluff. They make peeping sounds and follow their mother around like little fluffy robots.

Chicks imprint on their mothers. In the absence of a mother hen (such as when chicks are incubator-hatched), they will imprint on the first moving object they see. Sometimes that can be you!

Tiny newborn chicks are completely dependent on their mom for help navigating their new world. They need to be shown how to eat and drink.

chickens life

Young chicks are very fragile and wobbly. Their legs will take a week or so to get stronger as their muscles continue to develop.

Tiny chicks grow incredibly fast. They can double in size in the first month of life alone.

By the age of six to eight weeks depending on the breed you are raising (around 60 days for most), the young chicks have entered the adolescent stage of life – they are now pullets.

Chicken Life Cycle As A Pullet

Pullet is the term used to describe a chicken that is no longer a chick yet not quite an adult.

The pullet stage is the most awkward stage in the chicken life cycle. Pullets can seem to be all wings and legs, with patchy feathers and ungainly bodies.

It is important to watch pullets closely around adult chickens. Pullets are not yet as big and strong as adults and can get bullied in a flock setting.

Like the chick stage of life, the pullet stage can vary based on the breed of chicken. For most breeds, the pullet stage will last up until your chickens are about 20 weeks (five months) old.

This helpful video will walk you through the basic chicken life cycle stages from embryo through the start of adult life (six months). You can visually see how the chickens change and grow and look so different in each phase of life.

Chicken Life Cycle As An Adult

Female chickens (hens) may start laying their first eggs during the pullet phase of the chicken life cycle. If this happens, you may notice that the eggs seem abnormally small.

But not to worry – these are just “practice” eggs and your adult hens will lay normal, full size eggs once they become adults.

The adult stage of the chicken life cycle is also when male chickens become roosters. Roosters can be incredibly loud and very territorial around “their” hens. Roosters typically start crowing around the age of 18 weeks (4.5 months).

If you are reading this article because you are interested in keeping chickens for eggs or meat (or both) in an urban setting, check with your local regulations before you get started. Many communities do not allow roosters because of the noise level.

Healthy adult hens will typically lay one egg per day, although skipping a day here and there is also normal.

Adult hens will lay almost daily for at least the first one to two years of their lives. It is normal for hens to lay for about 10 months and then take a break. During this break, they will molt out their feathers and grow in fresh feathers.

chicken reproductive cycle

After the first year or few of adult life, egg laying may become less regular. Sometimes chickens will also stop laying when they are ill or when they are not getting enough light.

As The Farmers Almanac explains, adult chickens can live for seven years or longer under optimal husbandry conditions.

There is a lot to learn when you first start keeping chickens. The best place to begin is by getting a thorough grounding in the chicken life cycle as you have read about here.


This will help you plan for your chickens’ needs at each phase of life. You will know when to expect eggs or chickens that are suitable for providing meat. Raising backyard chickens as a family is also a great project to do with kids.

Your kids can learn about life by watching the eggs hatch and the chicks grow up. And your family can enjoy organic chicken eggs and meat that is safe and delicious.

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