A few hundred employees at a massive Smithfield Foods Inc. hog slaughterhouse missed work on Martin Luther King Jr. day after a union called for a walkout to protest the company''s decision to not make Martin Luther King Jr. Day a paid holiday, the Associated Press reports. The United Food and Commercial Workers Union estimated that 400 people among the 2,500 scheduled to work Monday morning walked out or did not come to work. The union has been running an organizing campaign at the plant and already lost one election. The plant continued with all operations. Workers sent a petition to management last week demanding the King holiday. The company said there wasn''t time to consider the request but workers could use one of their annual 12 unpaid personal days to observe the holiday. Anyone using up the personal days is subject to being fired after being warned, the company said. The plant in Tar Heel, North Carolina, about 80 miles south of Raleigh, employs about 5,000 people and is considered the largest hog processing plant in the world.