A dozen eggs in the supermarket is the easiest thing to just grab and go — no pulling a number, no bagging, no-brainer. Several decades ago, that was just fine, because most of what customers pulled from shelves were local eggs.

Today, if we care about where our food comes from, we don’t have the luxury of not paying attention. And anyone who pays attention has heard lots about sustainability, food safety and keeping money in the local economy.

But there are other reasons to buy local: to preserve the culture of Hawaii farms and support those who’ve put generations into providing sustenance to our community.

One such place is Petersons’ Upland Farm in Wahiawa, a longtime egg farm where a majestic hen house the length of a football field stands a story high on stilts. It is home to the farm’s more than 9,000 egg layers, who sit inside enjoying the tradewinds.

"My uncle designed that hen house and it amazes me every day," says Sharon Peterson Cheape, the farm’s assistant manager. "My brother and I and my cousins helped with installation. We learned electrical, construction, installation and plumbing, all on that house."

Peterson Cheape is the third generation of Petersons to run the farm, one of four remaining egg farms on Oahu. She’s a classic country girl: down-to-earth, generous, and kind to friends and strangers alike.

As Peterson Farm prepares to celebrate its 100th anniversary this fall, Peterson Cheape just wants to apologize: "I just want to say I’m sorry we sometimes have to close our egg room early, that we don’t always have enough eggs for everyone. It kills me, because some customers travel all the way from Waikiki and Kaimuki."

The room, a small, weathered structure bearing a painted wooden sign that reads "Egg Room," sells out of about 140 30-egg flats every day, short of what it takes to supply customers who come during posted hours of 7 a.m. to 4 p.m. daily except Sunday. ("We’re closed for church," she says.)

Last September, Peterson Cheape had to decide between renovating pens to give hens more space or rearing a new brood of chicks that would keep supply up. The babies require hours of hands-on attention each day for a couple of months before they become layers. After thinking long and hard, she decided on pens. Now that they’re finished, she’s back to tending chicks and expects a bigger supply of eggs in October and a full supply in April.

Behind the makeshift counter, workers sort eggs by weight on an old-fashioned scale as the eggs come out of a mechanized washer. Another worker "hand candles" eggs bound for the restaurants of chefs Alan Wong and Masaharu Morimoto.

Candling means inspecting eggs against a light to reveal interior quality. Eggs that pass muster are Grade A and head out to the restaurants. Because most of the rest aren’t candled, they’re Grade B.

With eight full- and part-time staff, Peterson Cheape’s goal is 14,000 layers, which would be plenty for the restaurants and egg room, plus more.

Richard and Jane Marshall have visited the egg room for most of their 30 years in Wahiawa.

"They’re fresh and they’re local, and that’s very important," Jane Marshall says. "It’s healthier, it helps the economy — it keeps things local. We do as much as we can."

Peter Fujimura, also of Wahiawa, says his favorite way of eating eggs is sunny side up, with a thin layer of white over the top. His wife has sent him to the egg room for about 30 years.

"I usually buy two dozen at a time and it lasts about two or three weeks, unless she bakes or makes salad," he says. "Living up here, we know the eggs are fresh. That’s one thing we’re grateful for: farm-fresh eggs."

As recently as the 1990s, Peterson Farm had 135,000 layers. Various circumstances led to downsizing, including the economic downturn and closure of the island’s only poultry processor.

"Since Pacific Poultry went out of business (in 2004), it’s been a struggle. In the life of a chicken, the bird has two to 2 1/2 years as a layer. Then it becomes a stewing hen. Feed is expensive; we can’t keep feeding birds who don’t produce," Peterson Cheape says. "Without a processor for these hens, all the farms had to downsize."

Now, stewing hens are purchased by customers who do their own processing.

But the Petersons come from hardy stock. It was in 1909, when James Hopper Peterson Sr., just 22, purchased 18 acres of land to begin his farm. He cleared the land of guava and lantana by day and slept in a tent at night.

The farm began with Jersey milk cows and chickens, but as the decades progressed, the chickens took center stage. In 1953, sons James (Peterson Cheape’s father) and Alan took over the business. The brothers still run things today.

"They’re 81 and 79, and they both work seven days a week," Peterson Cheape says with pride. "They still drive the forklift; they still collect eggs. I keep telling them not to, but this is such a part of them. Looking at them, I figure I’ve still got a good 30 years left in me."

Just like their dads, the third-generation Petersons grew up in farming, and Peterson Cheape says there’s value in perpetuating the lifestyle.

"I feel that agriculture is the heart of a community. It not only sustains us with food, it’s a way of life that teaches character and work ethics to our children."

Chef Wong has special ties to the Petersons, having attended school with one of the sisters. He also accompanied his parents to the farm as a child, paying weekly visits to the Egg Room.

"We bought the unwashed eggs because they were cheaper. My job was to wash them," he recalls.

The chef is a steadfast supporter of local food producers, for so many reasons. He discusses how more than 80 percent of Hawaii’s food supply comes from outside sources, and how vulnerable that makes us in our geographical isolation. He cites the $3.7 billion that leaves the state to purchase this imported food. If we could keep just 10 percent of that income in Hawaii, "just imagine the economic impact," Wong says. "If we’re less dependent on the outside, we can take care of ourselves that much more."

Wong says he’s particularly happy to support businesses in Wahiawa.

"I can buy my (ingredients) from any place, but it feels good to support businesses where I grew up, whether it’s Peterson Farm or Honda Tofu. Today, we’re witnessing lots of closings of mom-and-pop businesses. We’re losing a colorful part of our community. What little we buy helps them stay in business so that the next generation can continue. It’s history.

"For me, it’s about wanting guests to taste Hawaii. But it’s also about helping others. We should all be helping each other."

The achievement of turning 100 has come via hard work, determination, support of folks like Wong and dedicated employees, Peterson Cheape says.

"Several employees have been with us for over 25 years and one, who just passed away two years ago, had been with our farm for 55 years and worked with my grandfather. Our employees are like family to us and have helped us achieve our goal of continuing with our simple … way of farming," she says.

"There’s satisfaction in growing a healthy, nutritious product, and it’s so good to supply that to the community."