Wiktionary
pig run
n. 1 The running of a pig through an oil or gas pipeline 2 The open area of a pigsty
Usage examples of "pig run".
They both had a pig run away on the same day, and only one pig had been caught, which they both claimed as theirs.
There were two assistant principals at Warren Central High School to see students who had committed infractions, the worst of which was usually letting a pig run down the halls during senior week.