Pig tails are often docked to prevent biting, according to Peter Bahnson, assistant professor of swine medicine with the University of Wisconsin Veterinary School.
“It’s poor for the pig’s health if they chew on its tail,” he said. “It’s not well understood what starts tail biting, but once they get started, they continue more frequently.” Bitten tails are painful and can become infected, Bahnson said.