– In the loading docks, children sat in a darkened auditorium watching the animated movie “Moana.”

Where there were once racks of clothes and aisles of appliances, there were now spotless dorm-style bedrooms with neatly made beds and Pokemon posters on the walls. The back parking lots were now makeshift soccer fields and volleyball courts. The McDonald’s was now the cafeteria. All this made it difficult to visualize what the sprawling facility used to be — a former Walmart Supercenter.

The converted retail store at the southern tip of Texas has become the largest licensed migrant children’s shelter in the country — a warehouse for nearly 1,500 boys ages 10 to 17 who were caught illegally crossing the border.

The teeming, 250,000-square-foot facility is a model of border life in Trump-era America, part of a growing industry of detention centers and shelters as federal authorities scramble to comply with the president’s order to end “catch and release” of migrants illegally entering the country. Now that children are often being separated from their parents, this facility has had to obtain a waiver from the state to expand its capacity.

Cots are being added to sleeping areas. The staff is expanding. But even that is not enough. Federal authorities are considering establishing tent cities on Army and Air Force bases, and have already transferred hundreds of immigrant detainees to temporary housing at federal prisons.

The federal Office of Refugee Resettlement is now overseeing an estimated 100 shelters in 17 states, serving a population that has grown to more than 11,000 youths. One of the biggest concentrations is here near the border in South Texas, in the Rio Grande Valley, one of the poorest regions in the nation. There are about 10 shelters in three Valley counties, the majority in the Cameron County cities of Brownsville, Harlingen and San Benito.

The shelters in and near Brownsville have become big business, employing thousands of residents and bringing abandoned stores, schools and other buildings back to life in a county where the median household income is $34,578 and the percentage of those living below the federal poverty line is 29.1, far higher than the national poverty rate of 12.7 percent.

But they have also raised questions about federal oversight and management, and the invisibility under which many of them operate.

Numerous shelters that care for unaccompanied migrant youth in Texas have been cited by state child care facility regulators for dozens of violations in recent years, according to data from two of the state’s oversight agencies, the Texas Health and Human Services Commission and the Department of Family and Protective Services. The majority of the violations were for minor infractions, including incomplete child records. But some were for more serious problems.

At least 13 deficiency citations have been filed against the shelter at the former Walmart in Brownsville, which seemingly overnight became a symbol of the housing scramble after a Democratic lawmaker, Sen. Jeff Merkley of Oregon, showed up unannounced to take a tour but was turned away by police escort. Merkley’s attempt to gain entry this month, captured on Facebook Live by a member of his staff, put national attention on the shelter, which is run by a nonprofit group that contracts with a federal agency.

The mystery of what the Oregon senator was not allowed to see — the living conditions for hundreds of migrant boys inside a space originally built to house not people but cheap jeans and housewares — was seemingly solved Wednesday. Federal officials and the operator of the shelter, Southwest Key Programs, led several reporters on a roughly 90-minute media tour and question-and-answer session.

The shelter, called Casa Padre, is a world all its own, much of it invisible to outsiders. The few windows are covered in black mesh; in the parking lot, yellow-painted wooden barricades read, “Keep Out.”

Inside, it is clean, massive and brightly lit. Not far from the entrance, there is a large mural of President Donald Trump, an American flag and the White House, with a quote from Trump: “Sometimes by losing a battle you find a new way to win the war.”

A team of 48 medical staff and three on-call physicians provide medical services. X-rays and laboratory work are done in-house. The children receive classroom instruction for six hours a day Monday through Friday, and outdoor play time for two hours a day.

The building no longer resembles a Walmart. The interior has been redesigned, with walls and hallways constructed to create bedrooms, classrooms and other spaces. The mural featuring the president is one of many; one painting depicts former President John F. Kennedy with his words, “Ask not what your country can do for you,” in English and in Spanish.

Most of the boys are from Central America. Many of them smiled, waved at or shook the hands of the reporters touring the site. They were asked by the reporters and Southwest Key executives, in Spanish, “How are you?”

The constant reply was “Bien, bien,” meaning “OK, OK.” The media was not allowed to interview the children.

Some were leaning back, getting a shampoo at the sinks in the shelter’s barbershop, where a striped lit-up barber’s pole spun outside the door. They lined up in the cafeteria for dinner — chicken, mashed potatoes, mixed vegetables. One teenager sat at a cafeteria table with his head bowed and hands clasped, praying silently. Another told the cafeteria worker who served him dinner, “Gracias, Miss.”

Everywhere, some of the shelter’s more than 1,000 employees hovered nearby — they sat the ends of the cafeteria tables while the boys ate dinner, watched “Moana” with the children in the old loading docks and escorted lines of boys in the hallways.

Many of the boys appeared to be 16 or 17, and the few who were much younger, around the age of 10 or 11, seemed almost out of place. They wore gym shorts and sweatshirts, sneakers and rosary necklaces. One had his arm in a sling and another had his leg wrapped in a bandage. All of them are classified as unaccompanied minors by federal officials — they either crossed the border without a parent or guardian, or were separated from their parents as part of the administration’s new policy of arresting unauthorized border crossers and separating them from their children.

The vast majority, Southwest Key officials said, crossed the border unaccompanied.

In Bedroom 53, there were four beds on frames and one bed on a cot. The cot highlighted the housing crunch — it was one of hundreds of new beds that were recently added to boost the shelter’s capacity. In May, Casa Padre was licensed by the state at a capacity of 1,186. On Wednesday, after a variance approved by the state allowed Southwest Key to boost its population, the new capacity was roughly 1,500.

Southwest Key executives said the additional children do not make it too big to properly manage. They defended the services and the care they provide the children, as they will likely do when elected officials take tours of their own in the coming days, including Merkley. A congressional delegation is scheduled to tour the shelter Monday.

“We pride ourselves in providing excellent child care,” said Alexia Rodriguez, Southwest Key’s vice president of immigrant children’s services, adding, “We’re not a political organization. We take care of kids. We take great care of kids.”

The industry for sheltering young migrants had run into trouble here even before the latest boom. Hundreds of shelter workers in the Rio Grande Valley were laid off at the end of March, after several sites run on contract to the federal government by a private organization, International Educational Services, suddenly shut down. The organization, known as IES, lost its federal financing and shuttered its shelters and other facilities, for reasons that federal officials have yet to publicly explain.

Last year, a worker at a Brownsville shelter yelled at a child, causing the child to punch a wall. In 2016, children in a shelter in the Cameron County town of Los Fresnos were being told to sit down for four hours as a form of discipline. Shelters were cited in various cases after their employees pushed children, slapped their hands with a ruler or grabbed a wrist. Other violations involved a lack of supervision. One child ate a meal she was allergic to, even though she was wearing a red bracelet that listed her allergies.

A shelter in the Rio Grande Valley city of McAllen was cited in January after a child missed several doses of medication, and after children who complained of being in pain had to wait several days before care was provided. In September 2015 in Brownsville, medical staff left rubbing alcohol accessible, and a youth took it and consumed it. In October 2017 in San Benito, a random drug test found a shelter employee had showed up to work over the legal limit for alcohol.

The shelter at the former Walmart has been cited 13 times for deficiencies by state regulators since it was established in March 2017. In August 2017, an employee at Casa Padre made a belittling remark to a child in the presence of other children. One month later, a minor tested positive for a sexually transmitted disease. The medical coordinator failed to follow up, and the minor did not receive medical treatment until four weeks later.

On the tour Wednesday, Southwest Key and federal officials did not discuss such violations. They saw nothing wrong with the children spending most of their day indoors. They highlighted numerous phone booths around the shelter, including some the children use to call relatives and others that have direct lines to child protection agencies so they can lodge complaints. And they said there were some cases of children who tried to run away. The average length of stay in a migrant children’s shelter is about 56 days.

Asked if there were plans to house even more children at the former Walmart, Rodriguez said the new state-authorized capacity of roughly 1,500 was the maximum. “That’s it,” Rodriguez said. “We cannot put any more kids here.”