In the woods surrounding Chick-fil-A’s corporate headquarters, patriotic songs mix with hymns — “Amazing Grace,” “How Great Thou Art,” “The Battle Hymn of the Republic” — chiming from a bell tower. Near the front door, a bronze plaque proclaims the company’s purpose: “To glorify God by being a faithful steward of all that is entrusted to us. To have a positive influence on all who come in contact with Chick-fil-A.”

Faith is never far from the front lines at Chick-fil-A, which has become the country’s highest-profile business that touts the Bible as an operating manual. Chick-fil-A’s creed of “second-mile service” is a reference to Matthew 5:41, in which Jesus tells his followers that if someone forces them to go one mile, they should go two instead.

But as Chick-fil-A grows, it is trying to pull off a balancing act: selling chicken and milkshakes while not exactly selling Christianity.

“It’s not a Christian company,” said Dan Cathy, Chick-fil-A’s president. “It’s a company that operates on biblical principles. ... They really work.”

If the line between Christianity and biblical principles seems indistinct, perhaps the most vivid illustration of that separation is Chick-fil-A’s stores: They are, if anything, secular shrines to chicken.

Growth and scrutiny

A month ago, however, the company found itself fending off a rare controversy after gay blogs reported ties between Chick-fil-A and groups that lobby against gay marriage. As controversies go, it was fairly low-voltage: a Pennsylvania restaurant’s donation of sandwiches to a marriage seminar.

But the flap put the spotlight on the Cathy family’s beliefs and how they may influence the company.

For example, Chick-fil-A’s nondiscrimination policy covers sexual orientation where state laws require the company to do so, but not elsewhere, a company spokesman said. Likewise, Chick-fil-A offers domestic partner health benefits only in places that mandate such coverage. According to the gay rights organization Human Rights Campaign, 89 percent of the Fortune 500 mention sexual orientation in their non-discrimination policies, and 57 percent offer domestic partner health insurance on a nationwide basis.

In addition, the Cathy family’s WinShape Foundation incorporates religious teaching. A premarital program guides couples to a “successful Christian marriage,” according to the foundation’s website. A three-week romantic adventure for married couples is billed as time together, and with God. Dan Cathy said same-sex couples are not excluded, but the foundation’s curricula are not designed for them.

Chick-fil-A should codify what it has said publicly, said Jeff Graham, executive director of Georgia Equality, which advocates for lesbian, gay, bisexual and transgender people. “They say they don’t discriminate against anybody,” he said. “If they really mean that, why not put it into policy?”

As the company expands, it also becomes a bigger target. The Southern evangelical culture affirms many of Chick-fil-A’s values, but other parts of the country may not be so understanding, said Lake Lambert, dean of the college of liberal arts at Mercer University and author of “Spirituality Inc. — Religion in the American Workplace.”

“They have several challenges,” Lambert said. “They have moved out of the Southern culture and the Bible Belt.”

Success story

Dan Cathy, 57, is now the most visible front man for the company founded by his father, Truett, in 1967. He plays trumpet at New Hope Baptist Church and at Chick-fil-A grand openings, where he sometimes grabs a sleeping bag and spends the night in a tent.

There have been a lot of grand openings. Chick-fil-A now operates about 1,540 restaurants in 39 states and Washington, D.C. It has more than tripled sales to $3.58 billion in a decade. Last year was the 43rd straight year of rising sales.

“It was a small, regional chicken chain that has recently sprouted wings,” said Blair Chancey, editor of a fast-food magazine called QSR. Culturally and financially, “they are growing in significance.”

Cathy’s company is expanding steadily, but it does not change quickly. Its spelling-challenged cows and their “Eat Mor Chikin” signs have lasted more than 15 years — an eternity in the advertising world. In a quarter-century, there have been only two departures from the company’s top-level executive committee.

When the top bosses meet for retreats, praying together is one of the first orders of business. “We pray for God’s guidance,” Truett Cathy wrote in 2007. “It’s an important bonding time that says we are in one accord in what we do. We don’t have conflict.”

Chick-fil-A cultivates a conservative, traditional culture that emphasizes wholesomeness. Male employees wear dress slacks and Chick-fil-A ties, sometimes bedecked with cows. Beards are not allowed, but mustaches are OK. You won’t find a drop of alcohol at the company’s huge annual seminar, although operators may bring their spouses and catch family-friendly comedians. Employees wear name tags, the better to greet each other.

At headquarters, in College Park five miles southwest of Hartsfield-Jackson, some employees meet for a voluntary half-hour devotional at 8 on Monday mornings.

Closing on Sundays so restaurant operators can rest — and worship, if they wish — does not come cheap. Assuming about 14 percent of sales would occur on Sunday, the longstanding policy may have cost Chick-fil-A $573 million just last year. If so, it’s cash Chick-fil-A’s leaders say they don’t need. “Probably the best business decision we’ve ever made,” Truett Cathy once said of the company’s six-day week.

Striving for good service

Chick-fil-A’s business model is different from the typical franchise arrangement. It owns its restaurants and requires only a $5,000 investment from its restaurant “operators,” compared to hundreds of thousands of dollars at other chains. The company fielded about 1,500 applications last year from potential operators, but accepted only about 150. It’s easier to get a job at the CIA than at “CFA,” as the saying goes.

Tricia Whitthorne, 27, went through about 20 interviews before she could open her Chick-fil-A in Oklahoma City last year. “They want to make sure it’s something you’re entirely sold on,” she said.

Most operators have only one restaurant. They return 15 percent of sales to the parent company, as well as half the net profits — a higher cut than at other companies. But Chick-fil-A is able to retain its people: About 97 percent of the company’s operators stay in the system every year.

Job applicants say the selection process is concerned with whether candidates can run a business, not with where — or whether — they go to church. “They didn’t care so much about my beliefs as much as my willingness to serve at a level that they are aiming for,” said Kenny Loar, who worked at a Chick-fil-A restaurant in Atlanta and interviewed for a corporate job in 2009.

The company says its working environment is designed to be friendly and welcoming. The U.S. Equal Employment Opportunity Commission, which enforces federal laws against discrimination, has never sued the company.

Chick-fil-A restaurant operators receive hundreds of requests for food donations every year. Doug Lockwood, who opened a Chicago-area Chick-fil-A last year, says he gets no guidance from the home office regarding donations.

“People should understand there’s no hate and there’s no agenda,” Lockwood said. As for donating sandwiches to gay rights groups, “I would welcome it,” he said.

Bo Shell, art director at gay publication Georgia Voice, got a job at a Chick-fil-A restaurant in Milledgeville while in high school. The prayers before Christmas and Halloween parties weren’t his thing, but his boss didn’t pressure him.

“It seems so strange that someone as gay as me worked for Chick-fil-A,” said Shell, 27. “Of course there were Christian overtones, but I didn’t have a problem working for them if they didn’t have a problem with me. I worked with a lot of people who were really cool Christian people, and they were really supportive. I don’t regret working for them.”