Hidden behind the Banco del Sol and the Tienda El Nino is the economic pillar of this rural town: A massive factory that processes 130,000 chickens a day. Inside, headless plucked birds move along conveyor belts while 300 workers, in repeated deft strokes, slice each passing carcass into chunks of kitchen-ready meat.

For years, most poultry workers here were Mexican immigrants, including some who were in the country illegally. But last fall, after a tough state law against illegal immigrants took effect, many vanished overnight, rattling the town’s large Hispanic community and leaving the poultry business scrambling to find workers willing to stand for hours in a wet, chilly room, cutting up dead chickens.

“Even someone born and raised in Albertville may not have the necessary skills or be able to pass a background check,” said Frank Singleton, a spokesman for Wayne Farms, which owns the slaughterhouse. The firm held a job fair that attracted about 250 local residents, but few were hired, and some soon quit, daunted by the demanding work. Since the law took effect, he said, “our turnover rate has gone through the roof.”

Sponsors of the law say it has done exactly what they had hoped, driving tens of thousands of illegal immigrants from the state. The U.S. Justice Department has challenged some parts of the law, and President Obama’s announcement Friday of a temporary legal amnesty for more than 1 million young undocumented immigrants nationwide clashes directly with Alabama’s legislation.

“All our activities will be for naught if the president grants amnesty to everyone,” state Sen. Scott Beason, the chief sponsor of the Alabama law, said Friday. Still, with the U.S. Supreme Court expected to rule shortly on a similar law in Arizona, champions of the Alabama measure hope that their legal position will be largely vindicated. “If Arizona is a success, then Alabama will be a success, too,” Beason said.

The state senator said he had “absolutely no doubt” that the law, and the resulting exodus of illegal workers, has started putting more Alabamians to work. Beason noted that the state’s unemployment rate has fallen sharply since last fall, from 9.8 percent to 7.2 percent, and he said the new law was “a big part” of the reason. “I get phone calls from people thanking me all the time,” he said.

Nevertheless, a variety of employers in Alabama said they have not been able to find enough legal residents to replace the seasoned Hispanic field pickers, drywall hangers, landscapers and poultry workers who fled the state. There was an initial rush of job applications, they said, but many new employees quit or were let go.

Wayne Smith, 56, raises tomatoes on a family farm in the misty hills of Chandler Mountain, a 40-minute drive from Albertville. Last fall, he said, his entire Mexican crew ran off, and Smith and his neighbors scoured the area for new workers. The growers pay $2 for every large box of picked tomatoes, and a worker must be able to pluck fast all day, bent over in the hot sun, to fill two or three dozen boxes.

“The whites lasted half a day, and the blacks wouldn’t come at all. The work was just too hot and hard for them,” Smith said. He dismissed the argument, often made by critics of illegal immigration, that Americans might do the work if offered a higher and hourly wage. “We’ve been using Mexicans for 30 years, and now they’ve been run off,” he said. “Everyone is worried about Arizona. If this law sticks, what’ll we do then?”

‘A chilling effect’

Alabama’s law makes it a crime for illegal immigrants to buy a house, pay a utility bill or sign a contract. It also penalizes those who employ them, allows police to ask drivers at roadside checkpoints or routine traffic stops about their immigration status and requires schools to ask about the legal status of all new students.

Although there is no doubt that many illegal immigrants have left Alabama since October, studies by economists at the University of Alabama indicate that the drop in unemployment is partly due to other factors. They report that the number of workers overall has been shrinking, in part from ­baby-boomer retirements and in part from discouraged workers suspending their job searches.

At the Wayne Farms plant in Albertville, officials said that since the law took effect, they have spent more than $5 million to train new workers and compensate for lost production. Singleton said the factory had also lost some legal Hispanic workers, who left the state rather than be separated from their illegal immigrant spouses. “This law has created a chilling effect on the whole Latino community,” he said.

Today, the factory’s workforce of about 1,000 is a diverse and unstable mix. It includes Hispanics who have passed federal ID checks, local whites and blacks, and even a group of refugees from Ethi­o­pia and Burma, provided by an employment agency whose Web site offers, “We will help you clean house before ICE does it for you.”

In interviews in the factory parking lot, a few white and black workers said they had been hired recently. One middle-aged black man, who gave his name only as William, said he had been through some hard times and was grateful to have landed steady work. “A lot of Americans don’t want to do manual labor, but it’s an honest living, and it pays the bills,” he said.

A half-dozen Latino workers said they had legal papers, but several others said they had “borrowed” someone else’s ID. One young immigrant from Central America, who gave his name only as Juan, said he was making a decent wage at the factory but was afraid to drive his car, because his license had expired and he was not legally permitted to renew it.

“So many neighbors have left,” he said. “Nobody goes out at night. Nobody is calm. Nothing is certain.” At his workplace, he added, “there are more Americans now, Africans, even Asians. . . . Little by little, they are getting rid of us all.”

Hispanic leaders in Alabama said Friday that they are not certain how Obama’s amnesty for many illegal immigrants younger than 30 would affect the situation in Alabama. Salvador Cervantes, an activist who organized protests against the state law, called the president’s action “a great relief for all of us,” but he added that it was not clear how state officials would respond.

A town in upheaval

On the surface, Albertville, a busy town of 22,000, does not seem much changed by the new law. Its Hispanic community, which surged from near-zero in 1990 to almost 30 percent of the populace in 2010, is still very much in evidence. On almost every street, there are signs in Spanish — taquerias, peluquerias, Iglesia de Dios, Reyna Novedades.

But several trailer parks once fully occupied by Hispanics lie half-empty, and Hispanic store owners said there is less demand for items such as fresh tortillas and discount phone cards to Mexico, partly because some customers left and some of the others who stayed behind are reluctant to shop. They also said social interaction between Hispanics and others is stiffer.

“People who know me suddenly ask me whether I am legal,” said Mireya Bonilla, who has owned La Orquidea, a large Hispanic grocery and diner, since the early 1990s. Both white and Hispanic families still come in for lunch, but Bonilla said she feels less comfortable than before. “What’s hard is the way people look at you now,” she said.

Across the room, a white-haired diner who gave his name only as Bruce, said he had visited Central America and helped raise money through his church to fight poverty there. Yet he also said he supported the state law.

“I hate to see what’s happening to the Hispanics. Their community is suffering, and so is the economy,” he said. “But if the laws had been enforced 20 years ago, we wouldn’t be having these problems. Now we have this new law, so we need to give it time to work.”

Albertville Mayor Lindsey Lyons said the Hispanic influx had been a “double-edged sword” for the town, bringing crime and social problems as well as a source of labor and revenue. Since many illegal immigrants left, he said, there had been a drop in illegal drug activity, prostitution and car accidents. But he also acknowledged that some businesses had suffered.

“The bill has done what was intended, but it is not the permanent answer,” he said. “We need Congress to compromise and come up with a better immigration system. We want these people to learn English and become citizens.” If all the illegal immigrants left the area, Lyons added, “our industries would shut down.”

No one really knows how many of the state’s estimated 180,000 illegal immigrants have left or been replaced, but the rash of criticism from employers that depend on immigrant labor was so intense by this spring that Beason, the state senator, sponsored a revised version of the law to ease penalties for businesses that employ illegal immigrants.

Asked about employers’ recruitment difficulties, Beason said it would take time for Alabama natives to return to the kind of menial jobs they did before immigrants crowded out the field, accepting work for lower wages. He said he hoped that the law would improve the “work ethic” of young people and give jobless dropouts a chance to start over. “Using illegals has warped the job market and taken unfair advantage of them, too,” Beason said.

Living in constant fear

The outcry from legal Hispanic residents has been another unforeseen complication. Mexican communities here are a dense mix of legal and illegal residents, often within the same families. Some breadwinners who fled to neighboring states have returned to their wives and children, using fake work IDs or trying to stay invisible at home. Their legal relatives live in a shared state of tension, fearful of having family cars confiscated by police or documents rejected by suspicious clerks.

A few miles outside Albertville, Armando Macias, 43, lives in a trailer with his wife, Nora, and their two small children. The rooms are decorated with prayers and a candlelit shrine to the Virgin of Guadalupe.

Macias, who came to the United States in 1989, has a work permit. Both children are U.S. citizens, and the family has spent thousands of dollars on lawyers so Nora can become a legal resident. The parents said the new law has left them confused and scared, reluctant even to seek public vaccination cards for the children.

“People think we are illegal now because of our skin,” said Macias, who often drives up Chandler Mountain to work in the tomato fields. The family has had domestic problems and brushes with the law; Macias was once arrested for being drunk, and welfare workers removed the children until the trailer was refurbished. Still, the couple seem determined and united.

“We have made mistakes, but we are not criminals or terrorists,” Macias said. “We came here to work, and Alabama is our home, but now we’re not wanted.”