Are you looking to set up your own chicken coop? When you decide to keep chickens, it is important to do your research and that includes knowing which breeds would suit your setup the best as well as understanding the chicken life cycle.

Understanding the life cycle will help you grow healthy and happy chickens and get the most out of your flock. In this article, we explain what to expect at each stage of the life cycle of a chicken and how to look after them at the different stages.



Chickens will lay eggs even when they are not fertilized but they will only develop into chicks after fertilization. While the best rooster is usually the husband of the flock, the hens can be calculated when they choose a mate. A good mate will be not just the most impressive-looking rooster, but one that is also attentive and good at finding food.

A rooster will perform a courtship dance and if the hen approves of him, she will submit to mating. If not, she will simply ignore him or walk away. The mating itself is brief, taking less than a minute. If the egg has been successfully fertilized with sperm, an embryo will begin to develop.



If fertilization was successful, the mother hen will keep laying fertile eggs. She will gather them in her nest until she is satisfied she has enough. She then becomes broody and will sit on the eggs for the next 21 days.

However, some hens are not great mothers and won’t become broody even when they have laid fertilized eggs. In that case, you might have to find a surrogate hen mother for them or get an incubator.

As the mother hen sits on her eggs, she will ensure they stay warm and turn them over at intervals. If any eggs are not progressing, she will discard them. After 21 days, the eggs should start hatching but before the chick breaks through the shell, it will absorb the nutrients of the egg. These nutrients will support it in the early days of its life.

What Happens Inside an Egg?

The chicks begin to develop very quickly inside the egg and develop new body parts and organs every day. The chicks need full 21 days to develop fully. Sometimes they may hatch a few days early but this will affect their chances of survival.

On the first day after fertilization, the tissue and germinal disc develop inside the shell. Over the next two days the heart develops, blood circulation begins and the heart starts working. By day four, some limbs are forming already and the first feathers appear on day eight.

On day nine, the embryo resembles a chicken. The chick will turn on day fourteen so its head is within the wider end of the egg. The following day, the chick eats the egg white. On day eighteen it fills the whole egg and on day twenty it starts pipping. This means using their teeth to break the shell ready for hatching. They also consume the yolk.

You should never be tempted to speed up the hatching process but let them break out of their shells at their own speed. This is because as they are breaking through the shell, they are still absorbing all the goodness inside it.



When the chicks hatch, their down feathers are wet but they soon dry and become fluffy. After the chicks have dried off, move them to a brooder area. This is a room indoors that is kept warm with an infrared lamp and away from the rest of the flock.

What to Feed Young Chicks?

Your chicks will need a starter feed that is high in protein. The protein content should be 20-24% and they can start eating it from day one. They will also need vitamins and minerals and constant access to fresh water to ensure they grow strong and healthy and at a good pace. You can mix the food yourself or buy ready-prepared starter feed.

Because different breeds develop at different rates, you should always check the guidelines for your specific breed on when you can switch them to a less protein-rich feed. Usually, you can start introducing them to a more varied diet at the same time as you let them spend time outdoors.

How Fast Do Chicks Develop?

With most breeds, you will start to notice the chicks growing real feathers when they are five days old. The bones get stronger after twelve days, by eighteen days they will have most of their proper feathers, and you can usually tell their breed by the thirtieth day. As they develop their adult feathers, they will also sort out their pecking order.

You can start letting the chicks outside around eight weeks old but this varies across different breeds. As a general rule,  you should keep them in the brooder until they have their full feathers.

Pullet and Cockerel

Pullet and Cockerel

When the chicks are old enough to explore the outdoors, they move away from the chick stage and become teenagers. A female chicken that is no longer a chick but not yet a mature hen is called a pullet. A male is called a cockerel.

You can integrate the pullets and cockerels with the adults when they are approximately 2/3 of their full size. There will be more sorting out of the pecking order. While this is natural, keep an eye out for any signs of extreme bullying.

Introduce the cockerels to the flock before they have learned to grow. This is especially important if you already have roosters. They will need to sort out their standings within the flock and it is better to get it done early. Otherwise,  you could end up with your old and new roosters fighting continuously.

Pullets start to produce eggs when they are approximately eighteen weeks old but this depends on the breed. Their first eggs are smaller than the eggs from a mature hen. However, once the pullet has laid an egg, it is no longer an adolescent but a hen and its eggs will change over time.

What to Feed Pullets?

At the pullet stage, the chickens are still growing and developing so the best thing to feed them is grower feed. It will contain all the ingredients the pullets need to get them ready for egg laying. The grower feed has less protein than the starter feed, around 18%. Your cockerels can eat what the adult chickens do.

Hens and Roosters

Hens and Roosters

Chickens leave the teenage stage when they reach sexual maturity.  For hens, it means when they are ready to lay eggs, often around week eighteen. However, some people say all female chickens are pullets until they reach their first birthday.

Roosters will typically start to crow when they are about eighteen weeks old. This is a sign of maturity. They will also become more territorial and protective. It is also around this time when you want to decide what to do with your male chickens, especially if you have roosters in your flock already. Some people decide to sell them, others gull them.

As chickens get older, they move slower and have less energy. You might notice their legs and feet growing thicker and they may get arthritis. Their facial features change too and appear older. Depending on the breed, chickens live three to eight years on average.

Egg Laying

Adult hens are at the peak of their egg-laying ability for the first two years after maturing. If after a while, usually between ten months and two years, they start to molt and stop producing eggs, don’t worry. It is normal and they will resume egg-laying once they have grown new feathers.

Chickens’ egg-laying will become less regular as they get older and will eventually stop completely. However, If your chickens stop laying eggs before they get old, it may be caused by a lack of light or because they are ill. If it is a season with plenty of light, you might like to get a vet to check your hen over.

Feeding Laying Hens

When your pullets start laying eggs, you need to transition them to layer feed. It is not as high in protein but contains all the necessary nutrients and added calcium to support good health. Calcium will also make the eggshells stronger.

In addition, you can give your layer chickens crushed oyster shell feed in a separate feeder for extra calcium. Your roosters will not need the added calcium and can continue on grower feed or you can give them general poultry feed. The same can be given to hens that have stopped laying eggs.


The life cycle of a chicken has four key stages: embryo, chick, pullet/cockerel, and hen/rooster. It is important to know what your chickens need at each stage of their life to ensure they are happy and healthy.

If you would like to ask us anything about the chicken life cycle, you can write your question in the comments box.

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