Here.

“The numbers are stark. In 1967 there were 9,627 livestock (cattle, calf, hog and sheep) slaughtering establishments in the U.S. That same year, Congress passed the Wholesome Meat Act, requiring producers to use a USDA-inspected facility if they sell meat across state lines. A mass consolidation of the meat industry followed. Today, commodity meat is dominated by large companies. Just four companies sell about 85% of America’s beef and the pork and chicken markets are similarly controlled by huge corporations. By 2016, there were only about 1,100 federally inspected meat and poultry slaughterhouses in the country.”