A screen grab from an undercover video released by the Humane Society of the U.S. shows a pig in a gestation crate at Iron Maiden Farms in Owensboro, Ky. Courtesy of The Humane Society of The United States hide caption

itoggle caption Courtesy of The Humane Society of The United States

Breeding sows in crates at a subsidiary of Smithfield Foods in 2010. The photo was shot by the Humane Society as part of an undercover investigation. Humane Society/Associated Press hide caption

itoggle caption Humane Society/Associated Press

A Humane Society investigation of a Wyoming pig breeding facility to the introduction of an ag-gag bill in Wyoming, which eventually failed. Courtesy of Humane Society of the U.S. hide caption

itoggle caption Courtesy of Humane Society of the U.S.

Cows wait to be milked at a California dairy farm. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

Breeding sows in crates at a subsidiary of Smithfield Foods in 2010. The photo was shot by the Humane Society as part of an undercover investigation. Humane Society/Associated Press hide caption

itoggle caption Humane Society/Associated Press

At the JS West egg farm, south of Modesto, Calif., one chicken house has the new, spacious cages that egg producers and animal welfare advocates say keep chickens happier. Big Dutchman hide caption

itoggle caption Big Dutchman

At the JS West egg farm, south of Modesto, Calif., one chicken house has the new, spacious cages that egg producers and animal welfare advocates say keep chickens happier. Big Dutchman hide caption

itoggle caption Big Dutchman