The company generates more revenue per restaurant than any other fast-food chain in the US, according to QSR magazine.
Chick-fil-A's average sales per restaurant in 2014 were $3.1 million. Fried chicken competitor KFC sold $960,000 per restaurant, by comparison.
The sub chain Jason's Deli ranked a distant second with $2.7 million in per-restaurant sales, followed by Panera and McDonald's, each with $2.5 million in per-restaurant sales.
Despite its relatively small size, Chick-fil-A also ranks highly in terms of its total systemwide sales.
The chain generated nearly $5.8 billion in revenue in 2014, making it the eighth largest fast food chain in the US, according to QSR.
Chick-fil-A has only 1,950 restaurants, and none of its restaurants are open on Sundays. For comparison, McDonald's has more than 14,000 locations in the US, Taco Bell has nearly 6,000 and KFC has more than 4,300 - most of which are open seven days a week.
Yet Chick-fil-A generates more annual revenue than dozens of other chains that have more than twice as many locations in the US, such as KFC, Pizza Hut, Domino's, and Arby's.So what is the secret to Chick-fil-A's success?
Outside of the food, which gets high ratings from customers, many analysts point to Chick-fil-A's exceptional service.
The chain consistently ranks first in restaurant customer service surveys. In reviews, customers rave about the restaurants' cleanliness, quick, convenient service, and hardworking employees.
Excellent customer service is uncommon in fast food - an industry notorious for paying low wages.
But it appears Chick-fil-A doesn't pay much more than the industry average. Chick-fil-A pays about $8.44 an hour, according to Glassdoor. The average hourly wage in the fast-food industry is $7.98, according to PayScale.
Chick-fil-A says its service is so consistent because it invests more than other companies in training its employees and helping them advance their careers - whether or not those careers are in fast food.
Franchisees are encouraged to ask their new hires what their career goals are, and then help them to achieve those goals.
Business Insider/Hayley Peterson
For Kevin Moss, a Chick-fil-A manager of 20 years, supporting his team has meant funding an employee's marketing degree, and paying for another worker to take photography classes.
Moss says he also tries to support his employees in times of need. For example, if an employee's family member is in the hospital, he will send food to the family and hospital staff.
"I've found people are more motivated and respond better when you care about them," Moss told Business Insider.
The company also offers leadership positions in all of its restaurants that come with higher pay, as well as greater responsibilities. Crew members can work their way toward "director" positions in marketing, cleanliness, kitchen operations, and drive-through operations.
Many franchisees, including Moss, will additionally offer training classes for their employees to earn certificates in managing food and labor costs, managing conflict in restaurants, and other areas of expertise.
"The better we train, the longer people stay with us," Moss said.