About 3,800 workers at one of the nation’s largest meatpacking plants went on strike Monday in Colorado in what union representatives said was the first walkout at a U.S. beef slaughterhouse in four decades.

Hundreds of strikers picketed in front of the Swift Beef Co. plant in Greeley, owned by JBS USA, as the sun rose Monday. They walked back in forth in the morning cold, bundled in blankets as some yelled “huelga!” — Spanish for “strike.” Others carried signs saying “please don’t patronize JBS,” written in both English and Spanish.

The strike follows accusations from union officials that the company retaliated against workers and committed other unfair labor practices amid contract negotiations. A previous contract expired Sunday night.

“They don’t really value their workers and we’re the ones that help them get all their profit,” said Leticia Avalos, a 34-year-old union steward and Greeley native who has been working at the plant since 2020…

Company spokesperson Richardson said any employee who didn’t want to strike would have work and be paid. The company said it would operate two shifts at the plant Monday and would temporarily move production as needed to other JBS facilities…