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What Is The Life Cycle Of A Chicken?

What Is The Life Cycle Of A Chicken?

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Chickens undergo various stages throughout their life, from fertilization to adulthood. This article will discuss everything you need to know about the life cycle of a chicken. Keep reading to learn more.

We all love chickens, but how much do we know about their life cycle? What development stages do our backyard chickens go through?

What happens after a chicken’s egg is fertilized? If you plan to raise chickens, it is important to understand their life cycle.

Chicken Life Cycle

Stage 1: Fertilization

The life cycle of chickens begins before they are born. It starts with a rooster fertilizing a hen’s egg. Therefore, if you want to raise chicks, you will need to add a rooster to your backyard flock. 

During mating, the rooster will try to court the hen and put itself forward as the best rooster in the flock. Hens usually choose their mates carefully.

They tend to pay attention to various things, such as the appearance of the rooster, attentiveness, leadership qualities, and food-finding skills.

The mating behavior in chickens involves rituals like tidbitting, where the rooster in your flock will find something interesting and start calling the hens.

The rooster will then indicate the food by picking it up and then dropping it several times until the hens come to find out. Usually, the healthiest rooster in the flock wins out.

Chicken mating is a brief and precarious thing. A rooster usually mounts the hen from the back using his beak to hang onto her neck, feathers, or head and uses the claws and feet to hang onto her.

Hens squat in submission and raise their tail end up to meet the rooster. At this point, the hen will evert her cloaca ready to receive the sperm.

On the other hand, the rooster will avert his cloaca to allow the papilla to deposit sperm into the hen’s reproductive tract. The process typically takes less than a minute.

Once they are done, the hen will shake her tail and resume her business.

Once the two have mated, the sperm will begin its journey to fertilize the egg. Fertilization usually takes place in the infundibulum. Eggs usually remain in the infundibulum for around 15 minutes. If the sperm does not implant itself, the egg will be sterile.

Stage 2: Egg Embryo

The embryo stage in chickens begins once an egg is laid. Your hen can lay two types of eggs; infertile and fertile.

For an embryo to be formed, the egg must be fertile. Most eggs are usually fertilized, making them hatch into tiny chicks.

If your hens are broody, they will sit on the eggs to help them hatch.

If they are not broody or uninterested in sitting on the eggs to keep them warm, you will need to look for an incubator to get your eggs to hatch into chicks.

The embryo development process in chickens typically takes around 21 days. Several changes occur across the 21 days of the process.

The moment the egg is laid, the process begins.

1st Week

  • Day 1: Tissue stars to form and develop inside the chicken’s egg
  • Day 2: The heart is formed and starts beating
  • Day 3: The circulatory system starts to form, and the tails bud of the chick appears
  • Day 4: The limbs begin to grow. This includes the leg buds and wing buds. In addition, the eyes and brain begin to form.
  • Day 5: The elbow buds and knee buds develop and become visible
  • Day 6: The toes and beak begin to form. 
  • Day 7: The chick’s beak continues to grow. The egg tooth (what the chick uses to break out of the egg) will also appear. In addition, the comb will start to form.

2nd Week

  • Day 8: Ear canals open. Also, the chick will start to grow feathers.
  • Day 9: The little chick’s mouth opens up.
  • Day 10: Claws start to form. The egg teeth will also develop.
  • Day 11: The tail feathers begin to grow
  • Day 12: Scales start to form on the little chick’s legs and feet. Feathers will also become more visible on this day.
  • Day 13: Light feathers cover the body. Scales will also appear on the little chick’s legs.
  • Day 14: The body of the little chick turns so that the head is at the larger end of the egg

3rd Week

  • Day 15: The chick’s gut is formed and is drawn in towards the abdominal area.
  • Day 16: Feathers cover the chick’s entire body.
  • Day 17: The head draws down between the legs
  • Day 18: The entire body of the chick now fills the interior space of the egg.
  • Day 19: The yolk sac is absorbed (early the whole yolk sac)
  • Day 20: The little chick starts to use the egg tooth to break through the eggshell from the inside. This process is known as pipping.
  • Day 21: The little chick continues pipping and finally breaks out of the egg to hatch. Hatching usually occurs within 18 hours.

Unlike the births of humans and other animals, chicks usually move along very quickly. They develop body parts and new organs each day. It is amazing how much can happen within such a short period.

Chicks may sometimes hatch a few days late or early. However, this may likely affect their health by leading to various health issues.

If chicks are close to hatching, you should leave them be and allow them to break out of the eggshells on their own.

Chicken Life Cycle

Stage 3: Chick

The next stage in a chicken’s life cycle is the chick stage. The chick will come out of the egg with wet down feathers.

Usually, it does not take long for the feathers to dry off and become the fluffy chicks you normally see.

Once the chicks are dry and fluff, you can move them to the brooder. You will need to ensure that the area is warm and chicks stay there for the first few weeks.

They will need adequate clean water as well as food. Chicks should be offered food that is high in protein, minerals, and vitamins, to help them grow at a healthy pace.

Since different chicken breeds grow at different rates, you should be sure to research the breed of your chicks.

Most chicks will start growing their real feathers at five days old. They gain improved bone development after 10 to 14 days.

By 18 days old, most of their real feathers will have developed. After 30 days, they will start to look like their breed.

You can allow your chicks to spend time outside as early as eight weeks old. However, this depends on the breed.

Generally, chicks should stay in their brooder area until their full feathers have formed and developed.

Stage 4: Pullet

The term “pullet” refers to a teenage chicken. Teenage years in chickens vary from one breed to another.

However, most chickens are pullets when they reach 6 to 7 weeks old. They are characterized by patchy feathers and are smaller than adult chickens.

While pullets are bigger than chicks, they do not have the adorable appearance of an adult chicken. Most chicken breeds will not develop sexual differences until they are pullets.

These birds should be introduced slowly to adult birds in the flock. Because of their smaller size, they can be victims of bullying by bigger birds in the flock.

During their teenage years, they will start to assert themselves to decide where they fall in the pecking order.

They might peck at each other to assert dominance. You should not interfere with this unless it becomes violent.

The pecking order is a natural way that backyard chickens establish in a flock.

Chicken Life Cycle

Stage 5: Adult

This is the last stage in a chicken’s life cycle. Some birds may start laying eggs during the pullet stage. However, these eggs will be relatively smaller.

Many breeders and chicken keepers consider a pullet a hen when she starts laying eggs. Generally, hens have a much more mature appearance than pullets. 

Adult hens are more productive when they are younger. As they age, their egg production rate will fall.

The amount of egg a chicken can lay in a year varies from one breed to another. Some breeds are good egg layers than others. It also depends on nutrition and the general health of the chicken. 

As your birds change from pullets to hens, you should switch to a layer feed. This feed has less protein but is high in essential nutrients, such as calcium which aids in the formation of strong eggshells.

Chicken Lifespan

The lifespan of a chicken varies from one breed to another. It also depends on various things, such as health, genetics, care, and nutrition. Most chickens live between 4 and 8 years. 


While the life cycle of chickens might not be as long as that of other animals, it has many steps and details.

It is amazing to watch your chicken grow and develop. However, that cannot happen without proper care. Your birds will need all the essential requirements through every stage.

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