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When Do Chicks Become Chickens?

Barred Rock at 4 weeks old

The speed at which your cute fuzzy little chicks will change into their ‘finalized feathered form’ will absolutely blow your mind! That helpless tiny bird might weight a whole 5 ounces when you pick it up out of the box, but in just eight weeks it can be close to 7 lbs.

To put that in perspective, if you had a human baby that weighed 6 lbs at birth, then after 8 weeks it would weigh 140 lbs.

With this kind of rapid growth, it can be difficult to point at a specific time and say, ‘now you are officially a chicken.’ But if we were to assume, that adulthood is defined by the ability to reproduce, then roosters chicks are considered mature at around 4 months of age, while female chicks (hens) don’t reach maturity until 6 months of age.

Breed and season, also play a role in reproductive maturity, with some breeds growing faster and shorter daylight hours hindering development.

At What Age Do Chicks Get Feathers?

While that fuzzy down that covers your chick might be uber soft and adorable, the development of feathers is critical for their ability to maintain body temperature. Without this, supplemental heat is required as they will certainly perish without it.

On average, a chick will have completely filled out its’ main feathers at 8 weeks of age. However, you will see feathers started, long before that.

Point of fact, if you look closely, you will see flight feathers on the very tips of their wings, when you take them out of the box on day one.

By 4 weeks of age, they will have replaced the majority of their fuzzy down with normal feathers – leaving only uncooperative wisps around the neck. This makes them look like small gangly versions of their adult selves.

At 7 weeks of age, almost all remnants of that fuzzy cuteness will be gone. Comb and wattle development is still relatively unnoticeable, and their tail feathering still has a ways to go, but… for all intents and purposes, your birds’ feathering is finished.

At What Age Is A Chicken Full Grown?

While most chickens are able to reproduce at an early age, they aren’t finish growing. They will continue to ‘fill out’ for some time. This can be difficult to notice given the rapid growth that you may have become accustomed to observing those first 8 weeks.

For most breeds, a chicken will be finished growing at 12 months of age. This means that their height, weight and basic bulk will reach its maximum, and you really shouldn’t expect any further progress after this time.

However, there are a few notable exceptions to this.

Slower growing breeds like the Jersey Giant, will continue to grow until 18 months of age, a third longer than the average backyard chicken. And this extra growth time makes a significant difference.

For example, the Black Australorp has plumage that is very similar to the Jersey Giant, giving them a nearly identical appearance. And yet, an Australorp rooster may reach 8.5 lbs in weight where the Jersey Giant rooster typically weighs around 13 lbs at final growth.

Another exception to this 12 month rule, is the Cornish Cross. This breed of chicken was bred specifically for rapid growth and size. Consequently, the Cornish Cross is considered to be at final size at around 2 months of age.


Another aspect to consider with regards to chicks becoming chickens, is when they have reached the point where they no longer require intensive care.

Make no mistake, baby chicks fresh out of box, are in fact babies and need a LOT of help. From providing exactly the right temperature, to showing them ‘this is food’ and ‘this is water’, they are in need of your full attention.

Thankfully, this does not last long.

For our flocks, after the initial 72 hours, I no longer feel the need to check on them every 4 hours. And by the end of 8 weeks, I’m confident that they are mature enough to join the other birds, already established in the flock.

At this point, the only requirement I have is to let them out of the coop in the morning and make sure that they’re all secure inside the coop at night. This is not to say that I don’t check on them regularly all throughout the day – which is advisable for any livestock animal. But the birds are capable enough at 8 weeks to survive without baby sitting (provided food and water is established).

If you’re interested in seeing a biweekly record of a chick’s growth, check out, ‘Chicken Breeds’. Each one of the breeds listed, will have images of their progress, as well as, a general description of their unique characteristics.