Disease has lead to a 5 to 6% drop in hog slaughters in the past year, which has also lead to empty barns and challenges expanding this herd in a healthy way. There have been many new hog facilities built in South Dakota, where pork production has been growing at a rate of 7% to 8% a year. High input and feed costs is also putting pressure on the industry as no one wants to get into swine production and not make a profit each year.
https://www.agweb.com/news/livestock/pork/empty-barns-several-factor-shrink-us-swine-herd-and-slow-expansion