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Life Cycle of a Chicken: The 5 chicken Life Stages

“Which came first, the chicken or the egg?”

Countless years of debate and still no answer. Hopefully, this guide to the lifecycle of a chicken helps you realize that it doesn’t matter!

As long as the ritual-like chicken dance leads to hatching chicks, and the babies grow up to lay their own eggs. The chicken world spins madly on, and your mind should stay in peace. 

Stage 1: Fertilization

So, you decided to breed chickens. Get an inside look into what happens during this first stage of a chicken’s life cycle. Start with how eggs form and some “troubleshooting” tips for infertility.

The Birds And The Bees Talk

Let’s start from the beginning, the egg. All hens lay eggs, but not all hatch into chicks. For that to happen, you need a rooster. First, the rooster works to impress hens in a chicken courtship. 

a hen and a rooster mating in a free-range setting

The males strut their stuff and do a little dance around the female. If the hen likes what she sees, then she crouches over to receive the male.

Here’s a fun fact. Roosters don’t have a penis. They have a cloaca just like the females. As they mate, both cloacae come in contact like two rims of a cup. A single rooster can release up to five billion sperms into the hen in just a few seconds (1).

The sperm journey begins up the hen’s reproductive tract. The swimmers stay there until a yolk drops down. The tract has just two parts: the ovary, where yolks form, and the oviduct, where the actual egg forms. The oviduct is the longest part, divided into stations for egg formation (2). 

After roughly 25 hours, you have an egg! The rest of the life cycle officially begins.

Even Chickens Have Fertility Issues

Chickens can have trouble with fertility, just like people. Sometimes it’s a matter of low sperm count in unhealthy roosters. Overweight or underweight males don’t make good breeding stock (3). And the same goes for the hens.

But that’s not all. Some chicken breeds need more help with aiming their swimmers than others, especially rumpless breeds. Araucana, for instance, has an extra hard time mating. Backyard chicken keepers  physically assist them or use artificial insemination.

To mate, roosters move their rumps to align their cloaca with the hen. 

If all else fails, adoption is always an option. Buying eggs online is an excellent way to start the life cycle of a chicken. You can use an incubator or a broody mother hen to help hatch them.

Stage 2: Embryo Development

The eggs are here! Now you have to play the waiting game. It takes a few weeks before you have chirpy fluff balls. Here’s what you need to know while waiting.

Caring For A Broody Momma

First, you have to take care of the mother hen. Eggs need constant warmth from laying to hatching. A hen’s body heat is around 105°F, keeping the growing chick alive while it grows outside of a living body. 

A broody hen only leaves her clutch of eggs to poop, drink, and eat. So, you have to bring her everything she needs.

Make sure she has a comfy nesting box with soft bedding. If you can isolate her from other hens, that’d be great. Other hens might peck on her, or she can start an unwanted “broodfest.” So, get her out of the ward setting and move her to a private room to brood in peace (4).

a brown hen brooding in a nest box with a medium-sized brown egg on the side

Leave lots of food and water for the hen, too. Good quality feed is important, so she doesn’t get malnourished. Think of it as a hibernation. Better give her a protein-rich food to keep her filled up for hours of sitting.

When To Get An Incubator

Not everyone wants a hen to have a 3-week maternity leave. Hens stop laying while they brood. So if you want your best egg-laying chickens to keep popping out eggs, you might want to try a different setting option. 

Get another hen breed that doesn’t have a high egg production and goes broody quickly. These loving mothers can adopt the eggs and raise them while the biological mom goes back to work.

Or, you can choose a good incubator to replace your hen. Yes, it’s an expensive option. But it comes in handy if you have a lot of eggs to hatch.

21 Days of Development

Among the chicken life stages, egg development has the most drastic changes. Here’s a condensed day-to-day update (5).

Days 1-2

A lot of cell division happens here, forming different regions. Think of this as the initial setup phase. 

Days 3-6

You can do your first candle check during this time. You should start to see the blood vessels spread out. And the faint outline of a chick with eyes becomes more defined. It looks like a fetus in ultrasound at this point.  

Days 7-10

The wings, legs, and beak become more apparent, and the chick literally starts taking shape. You have a head and a narrow neck. Even eyelids and the egg tooth start showing. The different regions develop distinctly. 

The yellow yolk, or vitellus, supplies the food for the growing chick. The amniotic sac, or egg white, surrounds the embryo, giving it a safe space to grow. And the allantois is a pouch that helps with “breathing” and poop control. 

Days 11-13

You’re due for another candle check. Parts of the chicken continue to form, and it starts to look like an actual chick. You might see pointy claws and spikey feather follicles. Leg scales also develop at this time. As the chick grows, the other compartments start to shrink.

Days 14-17

Fluff starts growing, and the chick grows faster. The egg white or amniotic sac starts to disappear, and the yolk shrinks. The chick begins to change position for hatching.

Days 18-19

The chick absorbs the rest of the yolk, its main food source as it grows inside the shell. When it’s all gone, it’s ready to hatch.

Days 20-21

The baby chicken hatches!

Stage 3: Hatching

Eggs start moving, and little beaks poke out of shells. Today’s the day you welcome baby backyard chickens! Hatching chicken eggs is a cool thing to see. But if you’re doing this on your own, make sure you know what you’re doing.

top view of a hatching with its bottom still in the egg shell

A perk of having a broody hen is that you don’t have to worry about helping your chicks hatch. 

But if you’re doing it on your own, you should be keeping a close eye on your eggs by day 20. If you’re hatching bantams, start checking by 18 days. 

Unlike what you see in cartoons, chicks don’t just pop out after a few minutes. These babies are pretty weak. They pretty much “birth” themselves, so it takes time. The first thing you notice is little chirps. 

As soon as the chicks poke through the air sac, they breathe and do their equivalent of a baby cry. Then it uses its egg tooth to pierce through the harder shell layers. Its tiny wings and legs help the chick wiggle out of the shell. The whole process can take an entire day (6).

Stage 4: Chicks

Success! You have happy baby chicks. Twenty-one days just blew by! Raising chicks is the most time-demanding of the chicken life stages. Let’s find out what you need to know when taking care of baby chicks.

Setting Up a Brooder

Right after the chicks hatch, they need warmth again. Mom usually provides this. But for bigger groups, you can also put them in a brooder box.

A good brooder box has the following:

  • A safe heat source: You can use either a heating pad or a lamp. Just make sure it’s fire-safe, and you can adjust the heat up to about 100°F (7). You need to get the chicks used to the normal outside temperature slowly. 
  • Food: Healthy chick starter
  • Water: Clean water placed in a special chick waterer
  • Bedding: Soft but not dusty or toxic.

Shots And Boosters For Your Babies

Just like babies or other pets, vaccines help boost the chick’s immune system. It also prevents outbreaks of common diseases like Marek’s Disease, Infectious Bronchitis, and Fowl Pox (8).

From Fluff to Fabulous

Chicks grow at different rates depending on the breed. Hybrids like the ISA Brown were genetically designed to grow faster for processing and earlier egg-laying. Heritage breeds, like big Brahmas, naturally grow very slowly. 

a black and white hen with its chicks foraging on the grass

On average, chickens take between 2 to 4 weeks for feathering to start (9). But they still keep some of the down fluff to keep them warm until about 6 to 20 weeks.

Gender Reveal

You usually have to wait for at least a week or two until you know the gender of your chicks.  Because most chicks hatch looking exactly the same. And since there’s no telling their cloaca apart, you have to base it on their big kid feathers. 

But sex-linked hybrid chicks give it away when they hatch. Their fluff feathers are different for males and females from the beginning.

Moving Out 

When chickens are fully feathered, they can move out of the brooder. What an exciting time in the chicken life cycle. Pick or build the best chicken coop for your young chickens carefully. They need lots of space to scratch around and explore.

Stage 5: Pullet To Adult Chickens

The constant monitoring phase is done! The chicks are growing faster and need less care from you. Here’s a glimpse into the world of chicken puberty.

Hitting the Teenage Weeks Of The Chicken Life Cycle

At around six weeks, your chicks start to look awkward. Their feathers keep changing, combs start growing, and they all just suddenly get way taller. Congratulations, you have feathered teenagers in your backyard!

a flock of pullet chickens

Cockerels are taller with chunkier legs and more prominent combs. Pullets usually have duller feathers compared to cockerels. Even their combs and wattles are not as brightly colored (10)

The Status Quo According to Chickens

You’re familiar with this in high school. The popular kids are at the top of the food chain, followed by the jocks/athletes, regular kids, and the geeks. Surprisingly, it’s not that different with chickens. 

The group of chicks hatched at the same time have to stand out from one another. If you want to add new chickens to your flock. Now is the time to do it. The younger, the better, because it gives them more time to get used to each other. They set who’s boss by pecking weaker ones, hence the name pecking order (11).

“However, once set, the pecking order in a flock tends to be relatively stable, although maturing birds are likely to have a go at improving their position.”

Some breeds are naturally more aggressive and take the top spot. But young cockerels like a challenge and start sparring. It’s all part of growing up.

A Special Diet

Once you find out who the layers are in the flock, you change up their diets. Pullets get layer feed, and the ones destined for the table get grower feed.

The difference is that layer feed is high in calcium, and grower feed has more protein.

All Grown Up

Pullets usually start laying between 16-22 weeks. Yes, that’s a long-range. But that’s because it varies by breed. As soon as pullets lay their first egg, they officially become hens. And cockerels fully mature when they start to mate.

You’ve come full circle in around six months. Congratulations!

Final Thoughts

Phew! 20 weeks sounds like a long time. But each stage of the chicken life cycle keeps you so busy. Time just blows away.

There’s really a lot you need to know when it comes to breeding chickens. Just remember that not all chicks will hatch every single time. But luckily, you control most of the factors to make the most of the breeding and hatching season. 

The most sensitive factor for eggs and chicks is temperature control. As they get older, you have to worry about their food and space to keep everyone happy. Provide them with everything, and they reward you.


No, you can’t hatch an egg from the grocery store. Egg production happens for two reasons, eating and breeding. Supermarket eggs are for eating, so they are not fertilized. 

Let’s say a fertilized egg slipped into the mix. Will it hatch? Most probably not. Fertilized eggs need constant warmth for the chick inside to develop. Commercial eggs don’t have that kind of heat. So even if there is a fertilized egg, it won’t develop into a chick.

You’ll crack one open and probably see signs of fertilization, but you will not break an egg for breakfast and find a feathered chick.

Yes, chicks can die while hatching. Unfortunately, their chicken life span is cut short from lethal genetic factors and hatching conditions. Sometimes, baby chickens can suffocate before they get out. Make sure that the air sac end points upward. It’s the wider, less pointy end of the egg.

An upside-down egg gives the hatching baby chicken a harder time because the egg holder blocks its airway. Plus, the poor little chick doesn’t have room to turn around. Too much struggling can kill the chick.

At the sound of little chirps, stay nearby to check for mispositioned eggs. But don’t peel the shell. Let them make their own way into the world.

Your pullets are laying small eggs because they just started laying. Their reproductive tract needs to get used to this new process. It’s just like when you start baking. The first few cookies come out a bit wonky or different sizes. But over time, you get it right. 

Egg production also needs practice. Your young chickens get the hang of it quickly and become expert layers in no time.

Oh, and don’t feel bad about the small eggs. They still have a big flavor to them.

  1. The Only Good Broiler Breeder Egg Is a Fertilized Egg. Retrieved from:
  2. How Does A Hen Make An Egg? Retrieved from:
  3. Infertility In Poultry. Retrieved from:
  4. How To Work With A Broody Hen. Retrieved from:
  5. Embryonic Development, Day by Day. Retrieved from:
  6. Guide To Incubating And Hatching Chicken Eggs. Retrieved from:
  7. How To Care For New Baby Chicks. Retrieved from:
  8. Poultry Vaccines For Use On Organic Farms. Retrieved from:
  9. How Chicks Grow The First Year. Retrieved from:
  10. How To Tell If Your Chicks Are Male Or Female. Retrieved From:
  11. The Hierarchy Of The Chicken Coop And How To Stay In Charge Of The Pecking Order. Retrieved from: