Pig farming is one of the most popular kinds of animal agriculture in China and, since the 1980s, the scale of production has grown to a massive scale. In 2013, China produced 56 million metric tons of pig meat, more than six times that of the United States. According to researchers, the business of pig farming is just that — a business — and they say (unsurprisingly) that “some pork producers place too great of emphasis on reducing costs while ignoring animal welfare concerns.” In other words, there are millions and millions of pigs in China who are subjected to high-density conditions for their entire lives, and could benefit — to a greater or lesser extent — on welfare improvements. Though there are some national standards related to stocking density, there is much room for improvement, as “the range in the standard imposes a great degree of inflexibility on the management of growing-finishing pigs’ environmental conditions.”

This study by Chinese researchers looks to find out the “optimal stocking density” for growing pigs. While many advocates would rightly balk at such a research goal, the researchers were trying to find a density that would decrease aggression and other negative welfare implications, which is arguably a good thing. “As stocking density increases,” they note, “the percentage of negative social behavior increases gradually,” and they found that “pigs grouped at a high stocking density may perform less positive social behaviors because of long-term stress than pigs grouped at a low stocking density.” They also found that pigs had more lesions (related to aggression) and were dirtier (covered in manure) in high-density housing. Unfortunately, however, even though the researchers find unequivocally that “high stocking density reduced the welfare of growing pigs,” the researchers recommend medium density as opposed to low density, to “balance” animal welfare with cost concerns.

The article is a good resource for advocates interested in animal welfare issues in China, as well as how economics influence animal welfare concerns.