Mathematical thinking may seem like a high-level human function, but at its root, arithmetic depends on the ability to compare values, recognize changes in quantity, and understand that number and size are not the same thing. Chickens, it turns out, are quite adept at this.

Early Evidence: Chicks Can Count

One of the most revealing studies on chicken numeracy comes from the work of Dr. Rosa Rugani, a researcher in comparative cognition. In controlled experiments, newly hatched chicks were trained to recognize groups of objects—such as small colored blocks—and then presented with choices between different groupings.

When objects were hidden behind screens and moved from one screen to another, the chicks consistently chose the screen that concealed the larger number of items, even when the total quantity was hidden from view. This shows that the chicks were not merely reacting to what they could see—they were performing mental calculations.

In one experiment, chicks were shown sets of five and ten objects, which were sequentially hidden. The chicks followed the arithmetic (5 + 5 = 10) and approached the screen they “calculated” contained more items. This behavior indicates a form of object tracking and addition, a cognitive skill linked to early math development in humans.

Quantity vs. Size: A Sophisticated Distinction

Beyond counting, chickens also demonstrate an understanding that number and size are separate concepts. When presented with two sets of food items—one with more pieces but smaller size, and another with fewer, larger pieces—chicks were able to differentiate between quantity and volume depending on context.

This shows a level of abstract reasoning that was once thought limited to primates. Recognizing that “five grapes” is more than “three grapes,” even if the three are larger, requires the ability to distinguish numerical value from physical scale—a key component of early mathematics.

How Are Chickens Doing Math?

Chickens are not solving equations in the human sense. Their math skills fall into the category of non-symbolic numerical cognition—the ability to perceive and manipulate quantities without formal language or symbols.

Researchers believe chickens may use a mental system called the approximate number system (ANS), which allows for estimation and comparison of numbers without counting each item individually. This system is also present in human infants and many animal species.

In addition, chicks have shown the ability to track ordinal numbers—understanding that one group is more than or less than another, and even that a number falls in a certain position in a sequence. These are foundational mathematical skills in human development.

Implications for Animal Intelligence

The fact that chickens can perform basic arithmetic tasks forces us to reconsider long-held assumptions about their mental abilities. It reveals a kind of conceptual thinking that suggests chickens don’t just respond to stimuli—they make predictions, analyze outcomes, and make decisions based on abstract reasoning.

This growing body of evidence contributes to a broader recognition of bird cognition, which has advanced dramatically in the past two decades. While parrots and corvids (crows, ravens) are often cited as brainy birds, chickens are proving that intelligence is not reserved for the exotic or rare.

Why It Matters for Chicken Keepers

Understanding that chickens can count and reason—even at a basic level—has real-world implications for their care and enrichment.

• Chickens notice differences in flock size and may become distressed if individuals go missing.

• When feeding, they can distinguish unequal portions, which can affect pecking order and resource competition.

• Offering puzzle toys or foraging challenges that require distinguishing between quantities can provide mental stimulation, reducing boredom and promoting natural behaviors.

By recognizing their mental engagement, chicken keepers can make more informed, compassionate decisions that respect the cognitive lives of their birds.

A New View of the Chicken Mind

These discoveries place chickens in a new light. Far from the mindless cluckers they are often portrayed to be, they are observant, calculating creatures with a basic grasp of numbers and logic. Their cognitive abilities mirror some of the earliest stages of human child development, placing them firmly within the scope of serious animal cognition research.

The hen who finds her way back to the same patch of insects every morning, or the chick who selects the bigger food pile, isn’t just being lucky—she’s demonstrating memory, judgment, and quantitative assessment. The math might be simple, but the implications are profound.