Alexis Madrigal, writing for The Atlantic: A turkey today is not the turkey of yesteryear. For decades, animal breeders have been transforming the genomes of turkeys to make them grow larger. Since 1960, the weight of turkeys has gone up about a quarter of a pound each year. The average weight of a turkey has gone from 15.1 pounds in 1960 to 31.1 pounds in 2017. And most of that change has been genetic. In one study of a representative strain of turkeys, poultry researchers fed the same diet to turkeys from 2003 and to a control group of turkeys that were representative of that strain's genetic pool from 1966. On average, the 2003 females grew to 33 pounds. Their 1966 cousins only got to 16.3 pounds.