Chickens are believed to have originated from the wild red junglefowl species in Southeast Asia. Domestication of these birds likely began around 7,000 to 8,000 years ago in the region that is now Thailand and Vietnam. Over time, chickens were bred for various purposes such as egg production, meat, and cockfighting. Today, chickens are one of the most widespread and common domesticated animals around the world, with over 25 billion estimated to be living on the planet.