The Humane Society on Tuesday accused two pig-breeding facilities, one of which supplies retail giant Wal-Mart Stores Inc, of mistreating the animals by confining sows in cages during pregnancy.
In a video on the Humane Society website, sows can been seen chewing the metal bars of their cages and struggling to stand up. Some are scratched, bleeding and even dead.
Paul Shapiro, senior director of farm animal protection at the group, said Seaboard Foods and Prestage Farms Inc were the owners of the plants in Goodwell, Oklahoma.
"When it comes to the treatment of farm animals, few practices are more controversial than the extreme confinement of animals in tiny cages for their entire lives," he said.
The Humane Society said it is not seeking criminal charges against the companies.
"We found gestation crates overflowing with feces and urine because of a backed up sewage system, employees hitting pigs in the genitals and pulling their hair in order to move them from one crate to another, piglets with splayed legs duct-taped backed to their bodies," Shapiro said.
Seaboard Foods, a unit of Seaboard Corp, iFs the No. 3 U.S. hog producer and a supplier to Wal-Mart Stores Inc, while Prestage is the fifth largest U.S. pork producer, the Humane Society said.
Terry Holton, president and chief executive of Seaboard Foods, said in a statement that the company "strongly dispute any allegation of abuse."
"Animal welfare experts and professional groups have found no one method for housing gestating sows that is clearly better than the other when managed properly," Holton said.
Ron Prestage, who owns Prestage Farms with his parents and siblings, told Reuters the video did not appear to show any neglect or abuse at their farm. The company has initiated an internal investigation to ensure company policies were followed.
"There is nothing for me to defend in the video. We have both systems (gestation crates and group pens) and have for years," Prestage said.
Oklahoma is the fifth largest pig breeding state and the eighth largest overall hog producer, according to the U.S. Agriculture Department.
The Humane Society called for a halt to the use of so-called gestation crates.
Pork producers such as Smithfield Foods Inc and Cargill Inc have already reduced use of cages that hold pregnant pigs, but the crates are widely used by both Seaboard and Prestage, the animal welfare group said.
"This type of extreme confinement is exemplified in the pork industry where breeding pigs are often permanently locked inside cages barely larger than the size of their own bodies, unable even to turn around, essentially, for years on end," Shapiro said.
Shapiro said investigators for the Humane Society got jobs at the two breeding facilities late last year and shot video of the conditions.
The group said 70 percent of the pork industry confines its pregnant pigs to gestation crates, despite the European Union and eight U.S. states -- including California, Ohio and Michigan -- passing legislation banning the practice.
The welfare group advocates "group housing" for pigs, with pens that allow the animals to move around freely rather than being confined individually in cages.
"There are times when each system has its advantages," Prestage said. "If you have an animal that's gotten injured, it's much easier to treat them if they are in an individual crate. If they happen to be on the bottom of the pecking order, the other ones are just going to beat them up.
"On the other hand, if there is no fighting, you might decide they are happier in a group pen," Prestage said.