Domestic Chicken - Gallus gallus domesticus

With a population of more than 24 billion worldwide, there are more domestic chickens in the world than any other bird.

Physical Description

Although most people can recognize a chicken when they see one, this doesn’t mean that all chickens look alike. There are many different breeds of domestic chicken, each bred for unique traits that may include size, egg production, and ornamental plumage. You can see a stunning variety of chickens on display in the Maryland Zoo Farmyard, representing several breeds including Polish, Egyptian Fayoumi, Mille Fleur, Sebright, Silkie, and Cochin.


Domestic chickens are descended from wild jungle fowl native to Asia. Chickens have been domesticated for many thousands of years, with references to them in ancient China, Persia, India, Greece, and other parts of Asia. Some recent evidence suggests that chickens were domesticated in Vietnam as many as 10,000 years ago.

Introduction to North America

Because chickens are small, very adaptable, and easy to care for, they are widespread throughout the world. European settlers brought basic barnyard chickens with them to North America. Asian ornamental varieties were probably first introduced to North America in the 1800s.


Chickens are mostly raised for food production but can also make good pets. Many ornamental varieties have been bred for their striking plumage, including the Cochin from Vietnam, the Silkie from China, and the long-tailed Phoenix from Japan.

In the United States, chickens were raised primarily on small family farms up until about 1960. The primary reason for raising chickens was eggs, not meat. Chicken meat was considered a luxury rather than a staple of the American diet until about 1910. Farming families could count on eggs for steady, guaranteed income, and all members of the family – even the youngest – could participate in caring for the birds and collecting the eggs.

Over the course of the past century, the poultry business has grown into a large-scale commercial industry. Commercial production occurs on egg farms and meat farms, with different breeds of chicken being used for these two different production purposes. Selective breeding of commercial poultry chickens has progressed rapidly over the past few decades, resulting in the creation of highly specialized, single-purpose breeds. The commercial meat chicken now grows to its market weight in six to eight weeks, whereas 50 years ago it took three times as long. Laying hens today produce well over 300 eggs per year, whereas in 1900 the average production was 83 eggs per hen per year.

Current Status

There are billions of chickens in the world, but the rise of the modern commercial poultry industry has certainly suppressed variety. Certain breeds of domestic chicken are becoming increasingly rare. The Farmyard is the home for these animals at the Maryland Zoo.

Quick Facts:

Varies by breed

Diet- Herbivore:
Grains, corn, soybean, grass, insects, worms


Captive: 5-12 yrs

Conservation at Home

Penguin Encounters

New African Penguin Exhibit





Elephant Program


Animal Experiences

Rise & Conquer