In Minnesota, where hog farming is big business (oinker sales totaled $8 billion in 2010) hog rustling has become a problem.

A rash-or rasher? of thefts has farmers locking barns and installing video cameras. Nearly 750 pigs have been stolen in recent weeks.  Investigators for the Nicollet County Sheriff’s Office confess that they are baffled.

The thieves know the business,  farmer Tim Waibel tells the Minneapolis Star Tribune. They take only mature, market-ready animals, and they’re stealthy enough to get past security. Waibel’s farm has motion sensors and doors whose movement triggers alarms. “It gives us a sense of some security,” he tells the newspaper. “But believe me, I’m locking my barns.”

“Four years ago, when the hog industry was losing money, we’d joke about locking the barns and walking away,” says farmer Doug Wenner. “Now you lock the doors and wish somebody was there 24/7.”

Farmers are convinced that more than one thief is at work, since moving pigs is labor-intensive. To get 150 pigs out of barn in 10 minutes takes a gang, not just an individual.

As to where the pigs are being fenced, it could be anywhere within a 12-hour drive: hogs can be transported for that long before needing to be watered.