GREELEY, Colo. — Tin Aye died without ever laying hands on her newborn grandson.

Through her six decades of life, she endured a harrowing exodus from her homeland in Myanmar while pregnant with her only child, followed by 15 years in a refugee camp. She and her daughter, San Twin, managed to forge new lives in the United States.

But she could not survive her job inside a slaughterhouse run by the world’s largest meat processing company, JBS. She died last year, one of six people who succumbed to Covid while working at a plant in Greeley, Colo.

In crucial ways, much has changed for workers inside the long, low-slung slaughterhouse in Greeley, a city of roughly 100,000 people on the high plains of northern Colorado. In a new contract secured last summer, the union gained substantial raises from JBS, the Brazilian conglomerate that owns the plant. Colorado passed legislation mandating paid sick leave, after the state shut the plant for more than a week last year. Inside the slaughterhouse, dividers and partitions have been installed to help maintain social distancing.

But workers complain that many of the changes have been aimed at managing perceptions, while stubborn problems remain: not enough distance between people stationed at some parts of the assembly line, inadequate stocks of hand sanitizer, and subtle pressure to come to work even when they are ill.

“It gets thrown in our faces if we’re sick,” said Mariel Pastrana, 23, who has worked at the plant for nearly three years, and whose wages jumped from about $18 an hour to more than $26 under the new contract. “They keep saying, ‘Production is slow, demand is going up.’”

A spokeswoman for JBS, Nikki Richardson, disputed that characterization.

“Our focus throughout the global pandemic has been, and continues to be, to protect our team members from the virus and do everything possible to keep it out of our facilities,” she wrote in an emailed statement.

The Greeley plant, which paid $2,100 bonuses to workers who got the coronavirus shots, has achieved an 80 percent rate of vaccination, Ms. Richardson added. The facility has increased wages more than 50 percent over the past five years.

The experiences of workers at the plant reflect the lopsided apportionment of risk and reward within the business of turning cattle into beef.

The four largest meatpackers — including JBS — have collectively paid out more than $3 billion in dividends to shareholders since the beginning of the pandemic, according to a recent analysis from the White House.

At the same time, many cattle ranchers are going broke. People who work in slaughterhouses — among them immigrants from Latin America, Asia and Africa — say they still face a grim choice between their safety and their livelihoods.

“People are scared,” said Anthony Martinez, 52, a father of six who has worked at the slaughterhouse for more than three years. “We are putting our lives on the line.”

He is part of the so-called break chain — a crew of employees who labor in proximity, hacking whole cattle into smaller pieces.

“It’s heavy breathing,” he said.

After the state allowed the Greeley plant to reopen last year, management instructed people on the break chain to remain six feet apart, Mr. Martinez said — a step that slowed production. But last summer, workers were told to return to working within two feet.

The JBS spokeswoman declined to address the specifics of this case, while confirming that social distancing rules are variable. “There are some areas within our facility where team members have to move through the department,” she said.

Signs throughout the plant direct people to stay home when they are sick. But workers say supervisors still sometimes urge them to continue showing up.

“The signs are just there so they can say that they care for the employees, but they don’t,” said Agustina Gordo, 37, who has worked at the Greeley plant for four years.

Last year, during the first wave of the pandemic, plant managers told employees not to wear their own masks while urging them not to discuss Covid for fear of spooking the work force, said Ms. Pastrana. Now, not wearing a mask can bring disciplinary action, she added. Yet masks present their own dangers, fogging up glasses, and preventing line workers from seeing clearly as they are cutting meat.

The JBS spokeswoman said workers “have access to anti-fog wipes and spray to ensure they can safely conduct their jobs while wearing masks.”

More than a year after her mother’s death, Ms. Twin, 30, struggles to recount the story without breaking down.

“My mother was the only family that I had,” Ms. Twin said as she held her son, Felix, now 20 months old. “I said, ‘Please don’t work in the plant anymore.’ She said: ‘I have to pay the bills. I’m strong. I’ll be OK.’”

Ms. Twin’s mother was a member of the Karen ethnic minority, which has long engaged in armed struggle with the military in Myanmar. In the early 1990s, her family fled over the border to a refugee camp in Thailand.

There, San Twin was born. She spent her first 15 years in a bamboo hut without electricity or plumbing, while the family subsisted on donated rice and beans. Her mother cleaned houses, washed clothes and tended to pigs to earn cash.

When she was 5, her father — a former soldier — briefly returned to Myanmar and was killed by the military for desertion, she says. Friends found his body floating naked in a river.

When the family was offered a choice of countries in which to settle, it opted for the United States, having heard that anyone willing to work hard could find a job.

In August 2012, Ms. Twin and her mother arrived in Denver, knowing no one and speaking no English. They moved into a cramped apartment. Her mother got a job working nights at the slaughterhouse in Greeley. She car-pooled with other Karen immigrants, leaving at 1 p.m. and returning home at 4 a.m.

She started at $12 an hour.

“That was a lot of money for us,” Ms. Twin said.

Her mother’s job was taking cuts of meat off the assembly line, packaging them and putting them in boxes. She stood on her feet for hours. The line was fast and relentless. Sanitizing chemicals misted down from the ceilings. Bathroom breaks were infrequent: Sometimes, Ms. Aye urinated in her clothes while working the line, her daughter said. She came home with an aching back, swollen fingers and bruises on her legs and arms.

Ms. Twin got married in 2019, and was soon pregnant. Months later, she found herself following the emergence of the coronavirus in China. She imagined that it could easily spread inside a packed slaughterhouse.

By early March, a man who worked behind her mother had contracted Covid. She begged her mother to stay home. But missing work meant forgoing pay.

Three weeks before her grandson was born, Ms. Aye began coughing uncontrollably. Ms. Twin urged her to go to the hospital, but her mother continued to work, even as she developed a fever.

Early on the morning of March 28, 2020, Ms. Twin began suffering painful contractions and shortness of breath. She drove through a snowstorm to the hospital. A test revealed that she had Covid.

She called her mother. Ms. Aye was by then struggling to breathe. Ms. Twin finally persuaded her mother to go to the hospital. There, she was diagnosed with Covid.

Ms. Twin’s son was delivered later that day by emergency cesarean. The next day, as she lay in the intensive care unit, her mother called from another hospital. Doctors had told her that her Covid was advanced.

“She was calling to say goodbye,” Ms. Twin recalled. “She said, ‘I really want to see you, but I can’t see you anymore.’ She told me to work hard for Felix. Just believe in the positive view, and help yourself and others. And then she dropped the phone. I never talked to her again.”

Ms. Aye suffered two strokes and slipped into a coma. She was kept alive by a ventilator until she drew her last breath on May 17, 2020.

“I always feel that she’s by my side,” Ms. Twin said.

JBS later gave her $6,000 for her mother’s funeral arrangements, and never called to offer condolences, Ms. Twin said.

For negligence leading to the deaths at the Greeley plant, the federal Occupational Safety and Health Administration later fined JBS $15,615.

Almost as soon as Eryn Yates made it through her first trimester of pregnancy last spring, she started shopping for her dream nursery.

But getting the items she wanted turned into a nightmare.

The crib that she had ordered from Crate & Barrel arrived within weeks, but the rocking chair from Pottery Barn Kids was back-ordered for months, and then lost somewhere in transit. The delivery of the dresser she was going to use as her changing table was repeatedly postponed until West Elm informed her that it would be delivered in late April or May 2022 — more than six months after her daughter’s birth.

“I definitely thought that we were ahead of the game since we started ordering everything so early,” said Ms. Yates, 27, who lives in Winter Garden, Fla., and works in health care. “I was wrong.”

Global supply chain disruptions wrought by the pandemic have snarled the delivery of items as varied as medical devices, toys and Grape-Nuts. But perhaps no delays have provoked more familial angst in the last two years than those for baby items.

Unlike many products that are ferried through the supply chain, things like cribs, car seats and strollers for newborns have an unforgiving deadline in the form of a due date. And some parents-to-be, either superstitious or simply dilatory, hesitate to purchase baby items far in advance. That puts them at odds with supply chain turmoil that has sometimes made it necessary to buy items weeks or months ahead of time.

“When there’s a human on the other side of it who’s coming into the world for the first time, it’s a different ballgame,” said Sylvana Ward Durrett, the chief executive and a founder of Maisonette, an online marketplace for baby and children products.

Demand is unlikely to let up. Even with a declining birthrate, there were more than 3.6 million births in the United States in 2020.

The result of the baby-supply upheaval — besides higher prices and an ever-bustling hand-me-down market — has been an injection of new stress and uncertainty into an already emotionally delicate time. Expectant parents are scrambling to get items before they bring their babies home, and retailers and manufacturers are racing to reassure them that their goods will come, and devising hasty solutions if they won’t. Message boards on sites for new parents teem with complaints over back orders and repeated shipment delays. Retailers have become accustomed to soothing anxious parents-to-be.

“These are pregnant women that are all having their babies,” said Lauren Logan, the owner of the Juvenile Shop, a family-run baby retailer in the Sherman Oaks neighborhood of Los Angeles. “They are hormonal, but they are pregnant — they want their stuff. I don’t blame them. I want their stuff for them.”

Lead times for furniture and other items, made in Asia, Europe and the United States, are “longer than they’ve ever been,” said Ms. Logan, who has worked at the Juvenile Shop since 1979. Some products that used to take eight to 10 weeks to arrive now take 18 to 20 weeks, with potential snags all along the supply chain.

To help new parents, Ms. Logan has lent out floor models and products from the store’s warehouse, a stopgap that has relieved some pressure but that has also cost her business money.

“We are giving out loaner furniture, loaner chairs, loaner car seats, whatever it takes,” she said. “If people are having their babies, they need something.”

Maisonette, which works with nearly 1,000 vendors, said the bulk of products facing delays had come out of Asia, along with Peru, where Pima cotton for baby apparel and pajamas is produced. Babylist, a registry site, said retailers were having a particularly hard time keeping hot branded items like the Doona stroller, Snoo bassinet, Keekaroo diaper changing pad and Elvie pump in stock.

Sellers point to numerous supply chain problems, including the availability of parts and shipping containers, backlogs at ports, a lack of truckers and even logistical challenges once items finally arrive at warehouses or distribution facilities.

Production of a continuously sold item typically took 45 to 60 days, and it then required 12 days to travel across the ocean to California, said Joe Shamie, president of Delta Children, a major family-run seller of cribs and children’s furniture carried at retailers including Walmart and Pottery Barn. Now it takes a couple of months just to transport the items to the United States.

The cost of freight to import products has also skyrocketed, from under $2,000 to $15,000 or $20,000 per container, which the company has largely absorbed so far, Mr. Shamie said. A typical container can fit about 300 cribs, he said.

“We’ve had situations where we have a hot product and are rushing to get things in — this is not what this is,” he said. “This is a case of the actual system being broken down.”

Those kinds of challenges have led some sellers to diversify their supply chains and focus on best-selling products.

Million Dollar Baby, whose brands include Babyletto and DaVinci, has increased the number of freight carriers and trucking companies it works with in an effort to dislodge the shipping backlog, said Teddy Fong, the chief executive. It has also made the Babyletto Hudson and Lolly cribs, among its most popular items, a manufacturing priority in Taiwan.

Still, roughly 35 percent of Million Dollar Baby’s items are out of stock at any point, though they typically become available again in two to three weeks, said Mr. Fong, whose parents founded the company in Los Angeles in 1990.

“It’s all sorts of these stories and seemingly new bottlenecks that pop up every week,” he said. “It’s very frustrating because there isn’t a clear line of sight in terms of what needs to be done to get us out of the situation.”

On the receiving end are customers who don’t need another source of anxiety. First-time parents often research heavily before selecting strollers, cribs, car seats and other wares. And out-of-stock items can crimp registries; Babylist says new parents often select 100 to 200 items.

After Gina Catallo-Kokoletsos, 33, and her husband finally agreed on a crib from Pottery Barn Kids, her father placed the order as a gift in July. Originally, the crib was supposed to ship in October, giving just enough time before the couple’s baby was due in November. But when Ms. Catallo-Kokoletsos checked in September, she saw that the shipment date had been pushed to January.

“I called them, and they were like, ‘Oh, yeah, it’s going to be delayed.’ And I said, ‘Well, my baby is due before that,’” said Ms. Catallo-Kokoletsos, who lives in Chico, Calif., and works at an animal shelter. She ended up canceling the order and choosing a crib from a small company she had never heard of. That crib arrived on time, but other items on her baby registry, including a rocking chair, went out of stock before she could get them.

“I knew none of it was the end of the world,” she said. “It just kind of gets frustrating after a while.”

Further complicating matters for some expectant parents are deeply ingrained beliefs about buying or receiving items before their babies are born.

Joelle Fox, 35, a naturopathic physician in Scottsdale, Ariz., who is expecting a baby boy in January, said she was wary of ordering anything in part because of a custom among many Jewish people of not having baby things in the house until the baby arrives.

“It’s kind of a tradition that women have done, and I was kind of following that,” she said, adding that she also wanted to research items carefully to make sure they were not harmful. But the supply chain issues compelled her to start buying some items for the nursery at the end of October, a decision that she said prompted “a lot of emotions.”

Even still, she said, the dresser she ordered from Wayfair is not supposed to ship until mid-January. “That has definitely put a bit of a damper on everything, because I can’t get the room completely set up,” she said.

At around 36 weeks pregnant, Ms. Yates in Florida, whose daughter was born in October, gave up on receiving the West Elm dresser and bought one from Ikea. She cut off its legs and replaced them with metal ones that matched the crib she had bought.

She had less luck with her Pottery Barn Kids chair, which she had ordered in June. After it failed to arrive, she felt so desperate that she emailed corporate customer service and copied the chief executive. By the time she was told in October that the chair had been lost, the color and fabric she wanted were no longer available. The company ended up sending her a loaner chair, in a different color, “so I at least had something in the room for me to use.”

Ms. Yates said that she was sympathetic to the companies’ struggles, but that the ordeal still had left her in tears.

“I was not a very emotional pregnant woman — I had a very short temper, rather than being a crier,” she said. “But when it came to the nursery, I cried a lot, because I had this picture of exactly what I wanted, and then it just felt like one thing after another.”