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Do Chickens Have Brains? How Big?

You have probably heard the phrase “running around like a chicken with its head cut off.” Generally, this phrase means running around frantically or without reason. Another phrase that may come to mind is “bird brain.” These sayings may make you wonder whether chickens have brains. Well, the answer might surprise you. Chickens do have brains, but their brain anatomy is quite different from that of humans. In this article, we’ll explore the fascinating world of chicken brains, their anatomy, and their intelligence.

Anatomy of a Chicken’s Brain

anatomy of chicken head and brains

Do chickens have brains? The answer is yes, they do. However, their brains are not like human brains or even cat or dog brains, for that matter. A chicken’s brain consists of two hemispheres, each serving different functions. The way their brain functions allows them to do extraordinary things, like switching between monocular and binocular vision. In other words, chickens can use both eyes simultaneously to view the world or use each eye independently.

Monocular vision is handy for chickens in the wild, where they need to keep an eye out for predators. It provides a panoramic view of their surroundings, helping them stay alert and ready for any threats. On the other hand, chickens use their binocular vision to search for food and recognize other members of their flock.

This ability goes against the general consensus that birds are unintelligent. Within their brains, chickens can process multiple pieces of information at the same time. For example, one eye can be on the lookout for predators while the other forages for food. This remarkable ability makes sneaking up on a chicken a difficult task!

Aside from being laterally split, a chicken’s brain is made up of three parts:


The cerebrum is a section of the brain that is responsible for a higher level of mental processing beyond basic needs. Within the cerebrum is a chicken’s ability to analyze and comprehend a situation. It is also where movement, memory, and emotions stem.


Similar to the human brain, the hypothalamus of a chicken’s brain is the regulation center. The hypothalamus is where hunger and body temperature are put into equilibrium. It is also necessary for functions like sleeping, drinking, and other biological functions.


The brainstem is another essential component of the average chicken’s brain. Within the brainstem are the subconscious commands that keep animals alive, including breathing and digestion. In other words, the chicken brainstem is much like your own and contains all the structures found within it that are seen in even larger animals.

How Big is a Chicken’s Brain?

live chicken portrait

When looking at the size of a chicken’s skull, you would think that their brains are relatively small. This is true. A chicken’s brain is only a bit bigger than the size of one of its eyes. Depending on a chicken’s age and size, the biggest their brain can get is between a lima bean and peanut. For a more precise measurement, their brains are between 1.18 inches (3 cm) long, 0.4 inches (1 cm) high, and weigh between 0.83 to 0.97 ounces (23.7 to 27.5 grams). The brain accounts for about 2% of a chicken’s body mass.

Now for some startling news. Researchers from Linkoping University found that the size of the average chicken brain is decreasing. It is assumed that this is from years of selective breeding. It is hypothesized that chickens started developing smaller brains in order to adapt to the living conditions humans have placed them in. In the wild, on the other hand, chickens have smaller bodies and larger brains.

Where is a Chicken’s Brain Located?

The brain of a chicken is located farther to the back of the skull at a 45-degree angle. This is not like a human brain, which is centered at the top of the head in the skull. This unique location is one of the many distinctive features of avian anatomy, setting chickens apart from mammals, including humans. The exact location of a chicken’s brain is at the base of its skull, near the spinal cord. This arrangement serves a specific purpose in the life of a chicken.

The position of the chicken’s brain is not only a testament to the efficient design of nature but also a factor that contributed to the survival and adaptation of this species over time. Chickens are descendants of wild jungle fowl, and their brain placement has evolved in response to the challenges they face in their natural environment.

In the wild, chickens, like their ancestors, need to be highly alert to potential threats from predators. Their eyesight plays a crucial role in detecting danger, and the positioning of their brains facilitates this. By having the brain located towards the back of the skull, chickens can dedicate a significant portion of their frontal skull to house their large eyes, which provide them with a wide field of vision.

The position of the brain also supports a chicken’s posture and balance. Chickens need to be agile in order to escape predators or to roost safely. With the brain located towards the rear of the skull, they are able to change their center of gravity more effectively and thus maintain their balance more easily.

Can a Chicken Live Without Its Head?

The famous saying “running like a chicken with its head cut off” isn’t just a saying — it can actually happen. When a chicken’s head is removed, its brain is disconnected from the rest of its body. Sometimes residual oxygen can keep the legs moving independently from the body for a short time, resulting in the horrifying sight of a headless chicken running.

However, oxygen is not the only reason a chicken might keep moving when its head is long gone. There is one exceptional story that you may have heard about: The legendary story of Miracle Mike.

headless chicken mike

About The Headless Chicken, Mike

The remarkable saga of Mike began in 1945 on the farm of Lloyd Olsen, a farmer residing in Fruita, Colorado. One day, Olsen decided to prepare some chickens for dinner, a common and routine task on a farm. Little did he know that this particular day would mark the beginning of a truly extraordinary story.

As he went about the process of butchering the chickens, Olsen approached a rooster and made a fateful swing with his axe. However, to his astonishment, this swing didn’t result in the immediate demise of the chicken. Instead, the chicken continued to move and walk around as if nothing had happened.

The chicken Olsen had attempted to slaughter that day became a spectacle of curiosity and wonder. Mike, as he would later be named, defied expectations and captivated the imagination of all who encountered him. His headless existence seemed to challenge the laws of nature, leaving many baffled and intrigued. Mike was able to survive for 18 months before passing away.

How Did Miracle Mike Eat?

Naturally, the next question that arose was how Mike could continue living without a head. It was quickly discovered that Mike’s brain stem, a crucial part of the brain responsible for regulating vital functions, had somehow survived the ax’s impact. While most of his brain had been severed, this small, essential portion remained intact.

Understanding that Mike’s survival was unprecedented, Lloyd Olsen decided to care for the headless chicken. He began feeding Mike through a syringe, delivering a liquid diet directly into his throat. This act of daily sustenance became a routine, and it allowed Mike to live on in an almost surreal state.

The Legacy of Mike

Mike’s incredible story quickly spread, turning him into a bona fide celebrity. People from all over came to witness the headless chicken for themselves. He embarked on a tour across the United States, with Olsen as his manager, showcasing his remarkable ability to continue living despite the apparent impossibility of such a feat.

Sadly, Mike’s story, like all extraordinary tales, eventually came to an end. While he lived for about 18 months without a head, he did eventually pass away. It’s believed that a kernel of corn became lodged in his exposed throat, leading to complications that led to his demise. On March 17, 1947, Mike’s headless journey came to a close.

Miracle Mike’s story remains etched in history. Each year, Fruita, Colorado, where Mike once roamed headless, commemorates his legacy with the Mike the Headless Chicken Festival. This festival celebrates not only Mike’s astonishing survival but also the enduring spirit of curiosity and wonder that his story has come to represent.

How Smart Are Chickens?

The intelligence of chickens is a subject of debate. Those who have raised chickens know better than to call them unintelligent. Chickens may not have human-level intelligence, but they excel in their own ways.

Scientific studies have revealed surprising similarities between bird and mammal brains. Chickens exhibit problem-solving skills, social reasoning, and the ability to make assumptions. They can also recognize individual people and have distinct personalities, ranging from introverted to extroverted.

So while your chickens probably won’t display the same level of intelligence as a Border Collie or toddler, it would be a mistake to say that they do not possess intelligence.

Do Chickens Have Emotions?

Yes, chickens have emotions. The majority of chickens are seen as commercial egg-layers, but they are animals with emotions. Hens, for example, display strong maternal instincts and protectiveness towards their chicks. They can become anxious and distressed when separated from their flock due to their strong sense of community. Roosters display bravery and fearlessness when trying to save their flock from danger.

Chickens can also experience loneliness and grief when a flock mate dies. Some may even display unusual behavior, like casually pecking at a deceased chicken’s body if they’re hungry. When a hen senses her own death approaching, she may isolate herself, and other flock members often pay their respects by maintaining eye contact and softly cooing.

It is important to remember that emotions are also a form of intelligence and that many animals can display emotions in a variety of ways.

Final Thoughts on Chicken Brains

Do chickens have brains? Of course! While the average chicken brain is no larger than a couple of peanuts, they display surprising intelligence and can experience a range of emotions. Next time you observe your flock, remember that there is more going on in their minds than you may have originally thought!