Ever since it was coined in 1870, the bullpen was a roped off area in foul territory where late fans stood. Then in 1890s it changed and became associated with relief pitching, and now in 2021 PETA wants that to change.
According to PETA, “bullpen,” which is referred to the holding area where terrified bulls are kept before slaughter, want to change the term to a more modern and animal-friendly term called, the "Arm Barn!" At first I thought it was ridiculous but really, until you imagine a baseball announcer saying that a team has someone throwing in the arm barn or they are going to the arm barn early. I actually really dig it, and from now on I will say the Arm Barn because it's hilarious and sounds pretty cool.
“Words matter, and baseball ‘bullpens’ devalue talented players and mock the misery of sensitive animals,” says PETA Executive Vice President Tracy Reiman. “PETA encourages Major League Baseball coaches, announcers, players, and fans to changeup their language and embrace the ‘arm barn’ instead.”