Chick-fil-A, an American fast-food chain open for business a meagre six days a week, has retained the crown for most revenue per restaurant in the US, according to the latest report released by QSR magazine.

Chick-fil-A raked in revenues of over $4.4 million, more than doubling trendy competitors In-N-Out Burger, Chipotle, and Steak N Shake.

It’s next closest competitor is Whataburger, which generated $2.7 million per restaurant, a mere 61 percent of Chick-fil-A’s top line.

Chick-fil-A decimated the chicken industry, toppling over direct competitors Zaxby’s ($2.3 million), El Pollo Loco ($1.9 million), Bojangles’ ($1.8 million), Popeyes ($1.4 million), Boston Market ($1.4 million), Wingstop ($1.1 million), and the late great KFC ($1.0 million).

The secrets to Chick-fil-A’s ever growing success are threefold: superior drive-thru services, robust investment in employee training programs, and cult-like customer loyalty.

Chick-fil-A’s drive-thru operations have unfolded almost impeccably, finishing at the top of research firm SeeLevelHX rankings. This is important because it is estimated that anywhere between 60-70 percent of Chick-fil-A business is generated via drive-thru.

Customers documented that employees were more likely to say “thank you”, had an order accuracy rate of 97 percent, and displayed a pleasant demeanor in 9 out of every 10 visits.

Furthermore, customers find the drive-thru process to be amiable due to the face-to-face ordering process in which employees stand outside the restaurant taking orders on tablets, improving accuracy.

Chick-fil-A is able to attract hard-working employees in exchange for its cutting edge investment in training programs. As part of the recruitment process, Chick-fil-A asks employees to submit their career goals and then helps employees reach them through career advancement opportunities.

Perhaps most importantly, Chick-fil-A has a high customer retention rate. Their loyal legion of habitual chicken eaters pledge allegiance to the restaurant through thick and thin, even in the wake of an anti-Gay controversy that plagued the restaurant back in 2012.

Not bad for a fast-food chain founded on Southern Baptist values which limits operations to six days a week.