Are Chickens Dinosaurs: Yes Or No? (Related to the Theropods?)

Today we call them birds, and they are considered their distinct animal line, but chickens were in fact once dinosaurs. “Dinosauria” was introduced in 1841 by Sir Richard Owen during a series of public talks in Britain. The clade’s name was to mean “fearfully great lizards.” But translation is a strange art form, and now they are known as “terrible lizards.”

Regardless of which term you pick, they’re not phrases used to describe chickens. Yet science has mounting evidence that chickens are precisely that. 

Birds, including chickens, are the only surviving dinosaurs. The molecular evidence for this link was discovered inside a T.rex bone in 2003 by Jack Horner and Mary Schweitzer. Birds descended from a line of dinosaurs called theropods, who walked on two legs, such as the famous Tyrannosaurus rex.  

It is doubtful Colonel Sanders would have reached global success with a business named Kentucky Fried Dinosaurs. But there is mounting evidence for the miniaturization of theropod dinosaurs, a move that would spare them from the mass extinction that wiped out the rest of the “terrible lizards.” So how did a cold-blooded dino become a bird? For starters, dinosaurs were not cold-blooded.  

Did Chickens Evolve From Dinosaurs?

Palaeontologist Julia Clarke to Live Science, “Birds are living dinosaurs.” Hence, as chickens are birds, then chickens are a dinosaur. 

Thus, instead of people being hunted down by dinosaurs as depicted in the movies, it seems we are eating them. 

Are Chickens Related To Dinosaurs? 

Modern birds, including chickens, are descendants of non-avian theropods, which are dinosaurs. Thus, chickens are avian dinosaurs. 

Jack Horner’s Chickenosaurus

Palaeontologist Jack Horner has shown that chickens still carry the DNA to make a dinosaur. However, unlike using transgenesis to create a glowing pig, Horner is only DNA chickens have to create a “Chickenosaurus.”

Chickens have traits in their DNA that are turned “on” and “off.” For example, chickens have the instructions to make dinosaur traits, such as teeth; they’re just “off.” Thus, the project aims to turn these genes back “on” by “stimulating” them. They successfully turned the teeth back “on.” 

The project also looked into turning other genes on, such as hands and the awesome dino-tail. However, disappointedly, in 2020, Horner tweeted that the “tail” reduction “didn’t conclude with an atavistic gene.” Nonetheless, the project to create a “Chickenosaurus” continues. 

Researchers Made Dinosaur Legs On Chickens

However, it seems that some chicken genes also need to be turned off to recreate a dinosaur. This approach is how researchers in Chile created chickens with “dinosaur legs.” The gene Indian Hedgehog blocks chickens from growing long fibulae, so the researchers flipped it off, and the chickens’ fibulae extended like an Archaeopteryx (source). 

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Are Chickens T-Rex?

Chickens are not technically T-rex. It is more accurate to think of them as cousins. However, the T-rex is a theropod, which is where avian dinosaurs descended. 

But current science does indicate that T-rex’s closest modern relatives are the chicken and ostrich. Which doesn’t mean a T-rex would taste like chicken. After all, the ostrich doesn’t even taste like chicken but has a similar flavor to lean beef. 

What Dinosaur Did The Chicken Evolve From?

The science isn’t clear on precisely which dinosaur is in the chicken’s direct line of decedents, although they are theropods. Thus, chickens are in the same feathered “group” of dinosaurs as T-rex and Velociraptors. 

But how animals are related is a complicated business, and relatives can look drastically different from one another. For example, in modern-day animals, the turtle’s closest relatives are not lizards and snakes, as once believed. Instead, DNA sequence studies link turtles to birds and crocodilians. But nobody is calling turtles dinosaurs just yet. 

Are chickens theropods?

Chickens are theropods. Theropods were a group of bipedal saurischian dinosaurs, many of which were carnivorous. Birds, including chickens, are considered modern-day descendants of theropods, specifically falling under the subgroup called Maniraptora, which is part of the broader group Coelurosauria within the theropods. This evolutionary lineage shows that birds are not just related to dinosaurs but are classified as living dinosaurs, making chickens (and all other bird species) part of the theropod lineage.

A chicken roaming in a dust bath

Dinosaur And Chicken Evidence And Links

The exact link between chickens and dinosaurs isn’t established. There is clear evidence of avian dinosaurs. But who evolved and when is still a mystery scientists are exploring. The gaps in the overall evolutionary picture are why it is difficult to say which dinosaur gave us the chicken. 

Fossilized Oviraptorosaur Embryo Tucks Like A Bird

Scientists also know from the discovery of a fossilized embryo of an oviraptorosaur that the babies tucked themselves in their eggs just like birds when they’re nearly ready to hatch. Thus, it illustrates another link between birds and dinosaurs. But that doesn’t mean the oviraptorosaur evolved to become a chicken. 

Wonderchicken Is 66.7 Million Years Old

Evidence suggests there were already “chicken-like animals” around during the T-rex’s reign. The Asterionis has been dubbed the “wonder chicken,” and its fossil has been dated to be 66.7 million years old. It is said to share features with chickens and ducks, had long legs, and could probably fly. But rather than being a descendant of T-rex, it is contemporary. 

Read more on National Geographic here…

Welsh Dragon Is The Size Of A Chicken

Then there is the rediscovery of the Welsh Dragon, Pendraig milnerae. It was unearthed in the 1950s but only recently rediscovered, hanging out in an old drawer with some crocodile samples. It is the oldest theropod ever found in the UK and is related to the T-rex. But its remains do not evoke the image of a “fearfully great lizard,” but a creature the size of a chicken. 

Miniaturization Created Modern Birds

Thus, there are several theories of how chickens and other modern birds came to be since the time of dinosaurs. There are ideas that the birds came about through miniaturization, where the animals shrank. Part of the supporting evidence for this is that the head of birds, such as a chicken, bears a resemblance to infant dinosaurs (source). 

However, the miniaturization didn’t necessarily occur after the T-rex. As the Welsh Dragon shows, smaller dinosaurs were around 200 million years ago in the Late Triassic period. Thus, if the chicken came out of a mighty theropod or an already smaller one is unclear. 

T-Rex And Chickens Have Wishbones

But that doesn’t mean the T-rex doesn’t have chicken or turkey traits. As the Smithsonian pointed out to Americans in honor of the 2010 Thanksgiving, the T-rex has a wishbone, as did many theropod dinosaurs. Previously, the wishbone was thought to be a modern evolutionary bird trait. But now, there is evidence suggesting theropods may have been sporting them more than 215 million years ago.

Raising Backyard Chickens is fun and they have a lot of personality
Raising Backyard Chickens is fun and they have a lot of personality

T-Rex Wasn’t Cold-Blooded

The wishbone isn’t the only feature scientists once believed is new and may be pretty old. There has been mounting evidence that dinosaurs were not cold-blooded like lizards and snakes. While current science finds that dinosaurs were probably not warm-blooded, like chickens, they had warm-blooded characteristics (source). 

Scientists discovered this by examining the growth patterns. A dinosaur’s growth from infancy to adulthood has periods of rapid growth that are not possible in a cold-blooded species. However, their metabolic rate wasn’t high enough to be classified as warm-blooded. Thus, it is thought that they had endothermic and ectothermic traits. This means modern birds’ transition to warm-blooded wasn’t as radical as once believed.


Chickens are avian dinosaurs, the only type of dinosaurs to survive the mass extinction. Avian dinosaurs are theropods, just like the T-rex. However, that doesn’t mean chickens directly evolved from the Tyrannosaurus. Science only knows they are related and share some traits in their build, including a wishbone.