"The workers who are asking for the benefits and payments that they have earned, I think they're absolutely right and understand that what's happening to them is reflective of what's happening across this economy," Obama said.
Illinois Attorney General Lisa Madigan also said her office was investigating the company, which has not commented on the sit-in.
To their amazement, the workers have become a national symbol for thousands of employees laid off nationwide as the economy continues to sour.
"We never expected this," said Melvin Maclin, a factory employee and vice president of the local union that represents the workers. "We expected to go to jail."
The Rev. Jesse Jackson delivered turkeys, pledging the support of his Chicago-based civil rights group, Rainbow/PUSH Coalition.
"These workers deserve their wages, deserve fair notice, deserve health security," Jackson said. "This may be the beginning of long struggle of worker resistance finally."
Leah Fried, an organizer for the United Electrical Workers union that represents the workers, said the company told the union that Bank of America has canceled its financing. The bank had said in a statement that it wasn't responsible for Republic's financial obligations to its employees.
One of the factory's workers, Silvia Mazon, said in Spanish that she needs the money owed to her for an $1,800 monthly house payment. The 40-year-old from Cicero said she has enough money saved to survive for one month.
"We're making history," she said.
Rep. Jan Schakowsky, an Illinois Democrat, called it the start of a movement. "This story has resonated around the world," she said.
Associated Press writer Philip Elliott in Chicago contributed to this report.