By Helen Briggs BBC News
12 December 2018
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."