How hot can Philadelphia’s hot chicken scene get? There’s no sign of chill yet.

To see a food trend on fire, head to Northeast Philadelphia and drive west on Cottman Avenue from Roosevelt Boulevard.

It's home to what may be the city's highest concentration of hot chicken shops per square mile.

This chicken alley starts just beyond a gas station on the edge of Roosevelt Mall's parking lot, where you'll see a former shipping container painted flaming red with "Asad's Hot Chicken" in huge white letters. There will be a line of people at the window — there's always a line outside Asad's, a local chain.

Continue a few blocks, and more shops come into view. Next to the library on the left is a new building advertising Hot Clucks , another local chain. On the next block is yet another local, Nanu's . Also on that block are the nationally known Popeye's , Tex's Chicken & Burgers , and Jollibee . Ten minutes away on Frankford Avenue is a new OK Hot Chicken , an offshoot of local restaurants in Olney and South Philadelphia. A block from OK, national chain Hangry Joe's is planning its sixth location in the region.

Fried chicken sandwiches are not new to Philadelphia. We've had twice-fried Korean chicken for at least a decade, and they formed the basis of Federal Donuts & Chicken . Southern-style sandwiches began a national surge in 2020 when Popeyes Louisiana Kitchen rolled them out , and the trend heated up during the takeout and delivery spike that defined the pandemic.

Today's popular poultry product is hot chicken — specifically, sandwiches styled after Nashville hot chicken.

The national leader, the fast-growing Dave's Hot Chicken , has surpassed 200 locations in the United States and Middle East since opening in 2017 in an East Los Angeles parking lot. Its first Philadelphia store, the first of four so far in the region, opened earlier this year.

Locally, the trend can be traced to summer 2022, when Asad Khan, a then-23-year-old clothing manufacturer who enjoyed hot chicken during a trip to California, opened his first takeout at Cottman and the Boulevard. He signed on with third-party delivery services, fired up his social media, and watched the lines grow outside Asad's Hot Chicken , which now has 10 locations in Pennsylvania and South Jersey.

Then came the competitors, notably Nanu's , which opened last year and now has nine locations in the region, and Hot Clucks , which opened its first shop in Germantown last year.

The homegrown companies like Asad's, Nanu's, OK, and OMG (another upstart) are scaling as they grow, relying on extended families for efficient labor, setting up commissaries, and buying chicken — whose prices have moderated after a few spikes — in bulk.

Khan, of Asad's, said he was unsure exactly why hot chicken sandwiches took off around Cottman and the Boulevard. "People thought [hot chicken] was a trend, I guess, and started opening them," he said, suggesting a chicken-and-egg scenario.

One theory, supported by OK owner Berry The, is that the local chains, which all serve halal hot chicken , are catering to a growing Muslim population in lower Northeast Philadelphia.

"When I made the recipe, I wanted to make it for everyone, not just one group," said Khan, who grew up nearby.

Asad's, with its 203,000 followers on Instagram, seems to be the destination that the local newcomers are looking to emulate. Other shops have followed Asad's lead by giving away sandwiches at their grand openings and courting influencers.

Where did hot chicken start? Nashville has been the home of hot chicken since a Depression-era Lothario named Thornton Prince reportedly woke one morning to a plate of fried chicken prepared extra-spicy as punishment by a jealous lover. Her move backfired, as Prince enjoyed the heat so much that he created a restaurant, which great niece Andre Prince Jeffries now runs throughout the South as Prince's Hot Chicken Shack.

In its original form, Nashville hot chicken is cut-up chicken, brined in pickle juice and buttermilk, dredged in seasoned flour, fried in lard, and mopped with a glaze of butter, salt, and spices. It's served with pickle slices atop pieces of white bread, alongside plenty of napkins.

Today's hot chicken sandwiches Most of today's "Nashville hot" outlets build their menus around spicy boneless breasts and tenders, fried in vegetable oil, served with pickles on a brioche or potato roll, with a pinkish, mayo-based sauce and usually a rich, cooling slaw.

For the most part, the sandwiches are similar, despite their unique spice blends. OK's sandwich, for instance, calls to mind just a hint of sambal, the chile paste from Indonesia — which is where OK's owners are from.

All the shops offer chicken amped by spice levels whose scales top out as "scorchin'" (at Asad's), "insane hot" (at OK), "reaper" (at Nanu's), and "unbelievable" (at Hot Cluck's), plus fries, sides, sweet drinks and smoothies, and desserts.

The region's flock also includes one-offs such as Red Rooster Hot Chicken in Warminster. The field is getting more crowded by the day, and brands are scaling and expanding, seemingly overnight. OK is expanding into University City and Bensalem. Fire Nashville Hot Chicken , which opened in West Chester in 2022, now serves parts of Philadelphia through the ghost kitchen at 3300 Fairmount Ave. in West Philadelphia. Captain's Hot Chicken , also known as Doctor Hot Chicken, took off in Olney and is now open in Fishtown and is headed next to Bensalem. IDK Smash Burgerz & Nashville Hot Chicken , which opened several months ago in Old City, is teeing up locations in North and South Philadelphia.

At Nanu's, Ikram Rashid and his brothers were running halal food carts when they decided to jump on the hot chicken trend last year. Rashid said he developed the recipe in his commissary kitchen and enlisted friends and family members to get involved in the business. They opened on Cottman Avenue, down the street from the original Asad's. "Thank God people liked it," Rashid said. "We were just like, 'Let's go for it.'" They have at least three more locations on the way.

Rashid says that his motivation is his sibling Adan, nicknamed Nanu, the youngest of the four brothers. He has Down's syndrome, and "our parents were always worried about him," Rashid said. "They'd say, 'What's going to happen to him when he grows up and we are not alive?'" Rashid said. He and the other two brothers — Imran and Haroon — decided to set up the business to help support him. "They don't have to worry about it," Rashid said. "We got [his] back."