Chickens are among the world's most common animals and they provide us with a staple meat. They are also the most populous bird in the world and outnumber humans by about three to one.
This year, the Year of the Fire Rooster, the humble bird takes on a special significance. The Sunday Times uncovers some fascinating facts about the bird.
Which came first: the chicken or the egg? Nobody knows, but what is known is that the red junglefowl is the chicken's wild ancestor. It is native to the tropical forests of South-east Asia and can be found in Singapore.
Scientifically known as Gallus gallus, the red junglefowl is endangered here and has been spotted in nature spots such as Pulau Ubin, as well as in urban areas.
You know the theory that birds evolve from dinosaurs? Well, it seems there is truth in that when it comes to the chicken.
Scientists have shown an evolutionary link between chicken DNA and the preserved proteins found in a Tyrannosaurus Rex's leg bone.
While we are more familiar with the chicken as a domesticated animal that often ends up on our dinner plate,it was probably first reared for fighting and not food.
Cockfighting is believed to have originated in South-east Asia in ancient times and spread to other places such as India, China, Persia and Europe. A first-century mosaic found in the ancient Roman city of Pompeii depicts two roosters fighting each other.
Widely seen as a blood sport - roosters could be fitted with blades on their claws - cockfights are banned in many countries.
The chicken made history in 2004 by becoming the first bird to have its genome sequenced, which helped scientists study how a species changes through millennia of domestication.
Today, there are hundreds of breeds. The most populous is the Cobb 500, used by many commercial chicken meat producers. Others include Leghorn chickens, which are prolific egg layers; Orpingtons, a heavy chicken reared for meat; and ornamental breeds like the long-tailed Onagadori in Japan.
While we have likely seen only white or brown chicken eggs, they come in other colours too.
For instance, the Araucana, a breed of domestic chicken that originated in South America, lays blue eggs while the Olive Egger, a cross-breed, lays olive-green eggs.
Chicken eggs are also used in medicine. Flu vaccines are commonly made by injecting the vaccine viruses into a fertilised hen's egg.
Like humans, chickens can dream. They have REM, or rapid eye movement, a phase of sleep which signifies dreaming.
But, unlike humans, chickens have USWS, or unihemispheric slow-wave sleep. During this time, half the brain is resting while the other half is awake. This is why chickens sometimes sleep with one eye closed and the other open - to watch for predators.
And chickens may be just as smart as three-year-olds. Some studies suggest that chickens have cognitive skills akin to those of toddlers. In one, chickens were given more food the longer they waited to start eating. And get this, more than 90 per cent of the hens got it.
Comparable studies suggest many humans cannot show such self-control until they are four years old.
So, don't go calling the chicken a bird brain.
Silkie chickens have unusual features such as extreme fluffiness, black skin and muscles and bones underneath their fur-like feathers. They have a calm disposition and are often friendly towards humans, making them suitable as pets.
The Malaysian serama, a lightweight breed known for its puffed-up chest, is popular with breeders and collectors.
The Cochin has profuse feathering, even down to its feet, and is an indiscriminate eater, making it prone to obesity. It has an extremely gentle and docile temperament.
The Polish is a European breed with a distinctive feathered crest that impairs its vision, increasing its vulnerability to predators. It is mostly bred as show birds.
This article was first published on Jan 22, 2017.
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