A fowl sandwich has won the pandemic.

Fried chicken was already a sweet spot for the fast-food business before the coronavirus pandemic upended the economy. But it became a true restaurant star last year.

Restaurant tracker Technomic says sales at the 500 largest restaurant chains fell by 8% in 2020. Yet chicken-led brands enjoyed double-digit sales growth — yes, growth. And sandwiches were a key ingredient in that recipe for success.

It seems everyone is chasing this niche’s pioneer, Chick-fil-A, whose nearly $14 billion in 2020 sales was a 13% improvement from 2019. That growth came despite some crunchy competition — including the bucket-of-chicken king KFC — launching their own chicken concoctions. And don’t forget the smaller chicken sandwich specialists or eateries with broad menus that added this item, too.

Let me explain this rush to sell chicken on a bun.

Boredom

We were stuck at home. In-person dining was basically prohibited. So fast food became a top option when home cooking got stale.

But just how many times can you stomach that favorite burger? And at many chains, the alternative chicken options weren’t very good — until recently.

So, opportunities grew for a relatively new entree — the much-improved chicken sandwich. The industry’s fowl push came with lots of marketing dollars that lifted sales across the chicken segment.

Indulgence

The chicken sandwich has been fancifully spun by marketeers as an upgrade to traditional fast food.

For example, Popeye’s started the “chicken wars” by taking shots at Chick-fil-A in 2019, and it continues to playfully use social media to take on competitors over product “quality.”

To folks who had the cash, this kind of pitch offered a way to make dining out at least seem trendy in the pandemic era. But it’s still fast food. And for those with limited budgets, these popular and fast sandwiches provided an “affordable indulgence” as a rare treat.

Speaking of finances, chicken breasts run 20% cheaper per pound than ground beef. So they can be good for restaurant bottom lines, too.

Portability

It’s hard to beat the taste of a burger fresh off the grill.

But the pandemic era meant meals were consumed off-site through takeout or delivery.

How a meal looked and tasted perhaps 30 minutes or more later grew in importance. Food science suggests a fried chicken breast holds its just-cooked taste longer than many other meals.

Think about it. Who’d eat a day-old burger cold from the fridge?

Health

The pandemic certainly made folks think about their physical well-being.

Chicken has been long thought of as a healthier option than, say, beef. And perception can become reality at the cash register.

But this buzz-worthy meal isn’t a plain, grilled breast with steamed vegetables. Just look at the composition of popular chicken sandwiches — fried breasts slathered with secret sauces, cheese and even bacon.

So, I’m not convinced this item improves anybody’s chance of survival.

Breakfast

Chicken for the morning meal?

The square-burger chain Wendy’s figured out in March 2020 how to serve a morning meal. Two fried chicken items — in a croissant topped with bacon and maple syrup or in a biscuit drizzled with honey — powered the chain’s highly successful AM launch.

Meanwhile, fast-food giant McDonald’s added its own hot and spicy McChicken biscuit.

Oh, and Chick-fil-A has long been quietly known for its own spin on chicken and biscuits.

Spice

Some folks prefer their chicken sandwich taken up a notch or more.

If you didn’t know, the “hot” chicken sandwich — often peddled with various Southern city names attached — appeals to those who enjoy spicy foods.

Apparently, this is popular among young adults. They either have strong stomachs or enjoy watching their pals sweat.

Pickles

The “secret sauce” in Chick-fil-A’s flagship sandwich isn’t a spread, it’s two dill pickle chips grown and cured at the same farm in Wisconsin.

This condiment has become so iconic that few imitators have dared to serve a chicken sandwich without a pickle. Guess what: That also created another pandemic-era shortage.

No, we’re not talking about the marinated vegetable. Rather, there’s not enough glass to make canning jars for pickles.

This shortfall has slowed the debut of a late entrant to the chicken sandwich wars — Burger King.

Jonathan Lansner is the business columnist for the Southern California News Group. He can be reached at jlansner@scng.com