Modern meat chickens are four times the size of 1950s chickens
It starts with a 1940s breeding contest, and ends in a barn where one computer manages 45,000 birds.
The Economist · Why is chicken so cheap?The meat chicken sold today is four times the size of a chicken in the 1950s, and it reaches slaughter weight at about five to six weeks old. That speed comes from breeding, and then from how the birds are housed and managed to keep them growing that fast.
The breeding began in the 1940s with an American contest called the Chicken of Tomorrow. The aim was to develop a meatier bird that grew quickly and made protein cheap and plentiful, and it worked. The winning crosses became the ancestors of the modern broiler, a chicken bred purely for its meat.
A broiler now lives under conditions that are set in advance and held constant. On a high tech farm like the one run by David Speller, a British farmer and consultant who advises on farms producing about 3 million birds across Britain, 90,000 chicks can arrive at once. They are raised under artificial light and controlled temperature, watched with closed circuit television and carbon dioxide monitors. In one barn, a single computer looks after 45,000 birds, and just two workers can handle 200,000 birds.
The timetable is tight. Birds grow toward processing weight starting around day 34, with the largest leaving at around 39 days. Then workers have a frantic seven to 10 days to clean and warm the barn for the next batch, repeating the cycle seven and a half to eight times a year.
The result is a bird that depends entirely on controlled housing to survive to slaughter. If broilers are kept past slaughter age, they develop major health trouble because their bodies cannot keep supporting such rapid weight gain and cannot sustain growth beyond the normal slaughter point. By contrast, a barnyard chicken can live up to 10 years. The modern broiler is raised to be slaughtered at about five to six weeks.
Questions people ask
What did the winning Chicken of Tomorrow actually look like?
It was a national contest started in the United States in the late 1940s to breed a meatier, faster growing chicken. Breeders crossed Cornish and White Plymouth Rock lines, and the winning crosses became the basis for almost all modern broilers.
What goes wrong inside a broiler that lives too long?
Breast muscle grows faster than the skeleton and organs can support. That can mean weak legs, trouble walking, and heart failure, so weight that is profitable at five weeks becomes disabling if growth continues.
What does the barn computer actually control?
Sensors track temperature, humidity, carbon dioxide, feed, and water, and adjust heaters, vents, lights, and feed lines automatically. The goal is to keep tens of thousands of birds growing at the same steady rate with little variation.