Protesters face off with police last May outside McDonald's annual shareholders meeting. Organizers say this year's demonstration will be even bigger. Getty Images/Scott Olson

When McDonald’s shareholders gather for their annual meeting in Oak Brook, Illinois, later this month, they’ll be greeted by thousands of protesters, labor activists say. Organizers from the union-backed “Fight For $15” movement unveiled the plans in a video Monday -- the latest step in a three-year-long campaign waged against the fast-food giant. As shareholders discuss plans to boost the company’s slumping sales, cooks and cashiers will make noise outside, demanding $15 hourly wages and union representation.

“I should be able to afford to buy my son the milk he needs to grow up healthy, but that’s impossible on what McDonald’s pays me,” Adriana Alvarez, a McDonald’s worker, said in a statement released by organizers.

In 2014, about 2,000 McDonald’s workers protested outside of the shareholders meeting in Oak Brook, and 101 of them were arrested at a sit-in. But organizers vow this year’s demonstration will be even bigger.

The protest announcement comes at a tempestuous time for McDonald’s, which, amid declining sales and stock value, unveiled a turnaround plan Monday. It includes the conversion of some company-owned stores into franchises -- an uptick that would hike the share of franchises from 81 percent to 90 percent of McDonald’s locations worldwide. The company also announced plans to restructure its business into four geographic areas.

Last month, McDonald’s said it would boost pay for some 90,000 employees, but the move applied only to stores directly owned by the company, about 10 percent of its U.S. locations. As the company promises to turn more of its stores into franchises, the number of locations affected by the wage hike appears set to decline.

Last month, thousands of fast-food workers, joined by other low-wage employees, took part in demonstrations over pay and labor conditions for the third straight year. McDonald’s also faces a historic case at the National Labor Relations Board, where, for the first time ever, it is accused of committing labor violations as a “joint employer” along with its franchisees. The corporation has traditionally dodged labor-related demands by arguing its franchisees are independent business operators.

McDonald's annual shareholder meeting is scheduled for May 21.