Numbers Don't Lie: 71 Things You Need to Know About the World

by Vaclav Smil

In addition, broilers have been bred to mature faster and to put on an unprecedented amount of meat. Traditional free-running birds were slaughtered at the age of one, when they weighed only about 1 kilogram. The average weight of American broilers rose from 1.1 kilograms in 1925 to nearly 2.7 in 2018, while the typical feeding span was cut from 112 days in 1925 to just 47 days in 2018. Consumers benefit while the birds suffer. They gain weight so rapidly because they can eat as much as they want while being kept in darkness and strict confinement. Because consumers prefer lean breast meat, the selection for excessively large breasts shifts the bird’s center of gravity forward, impairs its natural movement, and puts stress on its legs and heart. But the bird cannot move anyway; according to the National Chicken Council, a broiler is allotted just 560–650 square centimeters, an area only slightly larger than a sheet of standard A4 letter paper. As long periods of darkness improve growth, broilers mature under light intensities resembling twilight. This condition disrupts their normal circadian and behavioral rhythms. On one side, you have shortened lives (less than seven weeks for a bird whose normal lifespan is up to eight years) and malformed bodies in dark confinement; on the other, in late 2019 you got retail prices of about $2.94 per pound ($6.47/kg) for boneless breast, compared with $4.98/lb for round beef roast and $8.22/lb for choice sirloin steak.