A study of chicken bones dug up at London archaeological sites shows how the bird we know today has altered beyond recognition from its ancestors.
With around 23 billion chickens on the planet at any one time, the bird is a symbol of the way we are shaping the environment, say scientists.
Evolution usually takes place over a timescale of millions of years, but the chicken has changed much more rapidly.
The rise of the supermarket chicken mirrors the decline in wild birds.
“The sheer number of chickens is an order of magnitude higher than any other bird species that’s alive today,” said Dr Carys Bennett, a geologist at the University of Leicester, who led the study.
“You could say we are living in the planet of the chickens.”
Chickens in numbers
65.8 billion – the number slaughtered in 2014, compared to 1.5 billion pigs and 0.3 billion cattle
25,500 – the number of stores in the world selling a popular brand of fried chicken
70% – the number of broiler chickens that are intensively reared (figures from 2006)
Five to seven weeks – the lifespan of a broiler chicken
3- 5bn – the population of the passenger pigeon in the 1800s, now extinct, which is thought to be the most common wild bird in human history.