The genetics of bigger chickens. Matt Ridley

Of all the amphibians, reptiles, birds and mammals in the world, the most abundant species is probably the chicken. At any one time, approximately 20 billion cocks and hens are alive on the planet (though never for long).

Chickens owe this abundance, of course, to their place on our table. About 90 million tons of chicken meat are consumed every year, plus 67 million tons of eggs, compared with 110 million tons of pork and 67 million tons of beef. Between 1970 and 2005, world production of poultry meat more than quadrupled.

The red jungle fowl was domesticated around 4,000 years ago in India, where it still calls cock-a-doodle-doo in tiger-infested forests. But the triumph of the chicken is relatively recent. Until a couple of decades ago, beef and pork outweighed poultry in the average American diet. Fifty years ago, chicken was a scarce delicacy in many European countries.

What accounts for the rise of cheap chicken? First, motorized transport led to the growth of the intensive broiler industry, in which food is brought to the birds rather than vice versa. Second, selective breeding led to birds that were more efficient at converting grain into meat. Remarkably, this genetic improvement even now shows no sign of tailing off.

Read full post in The Rational Optimist blog.