Why Chickens Don’t Fly

Chickens are just big birds. And bigger birds than chickens fly really well. So let’s find out why chickens don’t fly. Or at least why they don’t fly as well as, say, a hawk.

Wing Loading

The short answer is that chickens have small wings relative to their heavy bodies. That matters because of a thing called wing loading, which determines whether or not a bird can fly.

Wing loading is the relationship between a bird’s body mass and the surface area of its wings. It is calculated by dividing the bird’s weight in grams by the square of the upper surface area of both wings in centimeters. The formula looks like this: WL = weight(g)/wing area(cm²).

Assuming for the moment that the wings of all chickens are similar in size, wing loading would be higher for heavyweight breeds than for lighter breeds. And higher wing loading means less ability to fly.

The wing loading of most birds that fly well is no more than about 2 grams per square centimeter. The maximum wing loading that allows flight is about 2.5 grams per square centimeter.

Beyond that, the wings can’t produce enough lift to equal the bird’s weight. And lift is what allows a chicken, or any bird, to launch into the air.

A Look at Lift

Lift requires air movement over the chicken’s wings. How much air movement can be generated depends on how fast the chicken is traveling. And the higher a chicken’s wing loading, the more speed it needs for take-off.

A chicken could gain speed by making a running start, like an airplane taxis before take-off. Another way it could gain speed is by flexing its legs and springing into the air while flapping its wings.

Once the chicken is in the air, it maintains speed by continuing to flap its wings. High wing loading means a chicken has to flap more often than a bird of similar size but lower wing loading.

This amazing YouTube video show chickens taking flight both by flexing leg muscles and by getting a running start. Note that, to maintain speed while in the air, the chickens flap almost constantly.

Here’s another good YouTube video of chickens flying. Note how they tuck up their legs to reduce drag. Here you can see how chickens land. Landing is a typical problem for birds with high wing loading.

So, Some Chickens Do Fly

So, as we see in these videos, some chickens do indeed fly. And fairly well. But usually not far.

The official world record for the greatest distance of a chicken in flight is 301.5 feet. But Sumatras have been known to fly some 19 miles between the Indonesian islands of Sumatra and Java. Okay, so they probably get help from a stiff sea breeze, but still.

In addition to the Sumatra, other breeds with low enough wing loads to fly include Araucana, Old English Game, and Yokohama. Some bantam breeds also fly. However, most bantams have the same high wing loading as the larger breeds. Even though they weigh less, their wings have less surface area.

But Some Chickens Can’t Fly

Silkie bantams can’t fly because their poorly feathered wings don’t have enough surface area to provide lift. Likewise, any chicken that has missing or damaged flight feathers can’t fly.

Wing clipping reduces a chicken’s ability to fly. Clipping both wings increases the bird’s wing loading. Clipping only one wing not only increases wing loading, but also unbalances lift and flapping forces, causing the chicken to rotate when it tries to fly straight.

Some heavy breeds with high wing loading still manage to get airborne, usually by flexing their legs while flapping. But they rarely get more than a couple feet off the ground. And they can’t sustain flight for any significant amount of time.

Meaty breeds have especially high wing loading that make them unable to fly at all. Among the heaviest breeds, and therefore least able to fly, are Brahma, Cochin, Cornish, Jersey Giant, and Orpington.

Anyway, Who Needs to Fly?

All our domestic chickens are just fancy jungle fowl — ground dwelling birds that don’t migrate long distances. Jungle fowl find most of what they eat on the ground. They fly into trees to evade predators. On the ground they travel by walking. In trees they travel by flying from branch to branch in short bursts.

So they don’t need, and therefore don’t have, a strong flying ability to pass along to our modern chicken breeds. Plus most of today’s breeds are considerably heavier than jungle fowl, so their wing loading is even higher than that of their lighter ancestors.

Young chickens of any breed may fly around while they are exploring and learning about their environment. But once they reach maturity, most chickens, even those that can fly, have more important things to do.

Chickens that have plenty to eat and drink, shelter from the elements, and protection from predators find no need to fly. And besides, the process of getting airborne and sustaining flight is energy intensive. Simply put, most chickens have little interest in wasting their energy engaging in flight. So that’s why chickens don’t fly.