Examination of ancient remains by mitochondrial DNA confirms chickens arose from the Red Jungle Fowl in Thailand and India, not China, where ring-necked pheasants remains have been erroneously identified as chickens. But, the Red Jungle Fowl was also crossed with the Grey Jungle Fowl (sonnerati) to give the yellow legs found in present-day chickens.
The birds were introduced to Europe by the Phoenicians in the 8th ? century and Vikings took chickens to Iceland in the 10th century.
Some selective breeding took place under the Romans, to give regional different chickens.
From India, the birds spread east across Indonesia and South China, into Malaysia and the Phillipines.
The 19th century in the UK and Europe and the USA carried out further selecting, both for appearance and for egg production. Chickens became largely broken down into white egg laying breeds and brown egg. They have consequential side issues which have come to light.
For example, white breeds are less likely to indulge in injurious pecking than brown.
This resulted in the Netherlands increasing white flocks from 45% in 2013 to 65% in 2017.
Improvements in egg number and quality globally have reduced feed consumption by 57 million tonnes, releasing 8 million hectares of land from wheat production between 1995 and 2015.
Trading of eggs between countries became a large feature at the end of the nineteenth century, and by 1928 the UK was importing 3 thousand million eggs of the 5 million thousand being consumed, at a cost of £16 million. The government realised something must be done and took a hard look at marketing, of which more at another time.
As an example of the scale of international trade, and the spread of prices, figures from 90 years ago, in 1930, give a good illustration.
Eggs per long hundred (120 eggs) London
|Danish (15lb)||24s 6d|
|Dutch (Brown)||24s 6d|
|Dutch (mixed)||22s 9d|
|French (Brittany)||17s 6d|
|Polish (Blues)||12s 6d|
|S. Africa (16lb)||19s|
|S. Africa (15lb)||18s 9d|