Holy chickens: Did Medieval religious rules drive domestic chicken evolution?

Chickens were domesticated from Asian jungle fowl around 6,000 years ago. Since domestication they have acquired a number of traits that are valuable to humans, including those concerning appearance, reduced aggression and faster egg-laying, although it is not known when and why these traits evolved. Now, an international team of scientists has combined DNA data from archaeological chicken bones with statistical modeling to pinpoint when these traits started to increase in frequency in Europe.

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