Are Chickens Mammals?

Chickens are not mammals. They are birds. They have feathers as opposed to hair or fur, and they have wings, even though they don’t fly very well. They lack the teeth that most mammals have, they exclusively lay eggs, and they don’t nurse their chicks with milk.

It is true that a few birds do feed their chicks with crop milk, but chickens do not. Even birds that produce crop milk aren’t considered mammals.

As birds, chickens are much younger than mammals, and the order they belong to, Galliformes, survived that asteroid that plummeted to earth and wiped out the non-avian dinosaurs and arboreal birds 66 million years ago.

The removal of the dinosaurs allowed birds and mammals to develop into the variety of forms that survive today. Indeed, birds were just getting started as a class of animals around the time of this extinction event.

Why Would People Think Chickens Are Mammals?

People may think of chickens as mammals because they are often found on farms with other livestock such as cows, sheep, pigs, and horses, which are all mammals. People also eat the meat of chickens, which some consider healthier than the meat of cows or pigs.

Unlike mammals, chickens don’t have fur or hair, they have feathers. This and other features set them apart from mammals. Although, birds can sometimes have bristles on their heads and faces, this doesn’t define them as mammals. They are however, warm blooded creatures that breath air, posses vertebrae, and have some other mammal qualities.

Chickens are also kept as pets like dogs and cats. They like to live in groups that are hierarchical and more or less cooperative and looked after by a male rooster. They are devoted parents, like most mammals. What is interesting is that chicks are precocial, which means they are ready to fend for themselves shortly after hatching. Precocial babies are unusual for mammals.

Still, hens take great care of their chicks for their first few weeks of life, the way mammals do. Hens not only don’t produce milk but don’t directly feed their babies like other birds. Instead, she leads them to food and water, and they help themselves.

Next Up…

• Chicken Teeth: Do Chickens Have Teeth? – Everyone knows that chickens have beaks, but do they have teeth? Click to find out!
• Can Chickens Fly? – Have you ever seen a chicken fly? Can they? Click to learn more!
• Chicken Lifespan: How Long Do Chickens Live? – Ever wonder how long a chicken’s natural lifespan is? The truth may surprise you!