By Alyssa Oursler

Munchers in America may not be too excited by Colonel Sanders' drive-thru fried chicken these days, but they're going crazy for Taco Bell's Dorito Loco Taco.

Sales of the snack -- seasoned beef, cheddar cheese, sour cream, lettuce and tomatoes tucked into a crunchy Doritos shell -- recently reached 200 million after debuting in March, making it the most successful product since the chain began 50 years ago.

Taco Bell is the youngest child of parent company Yum Brands (YUM), which also runs Pizza Hut and KFC. While KFC is the most seasoned of the three -- kicking things off in 1952 -- it's lagging in the U.S. by a landslide.

Luckily, the Dorito Taco is here to help. After all, isn't that was family is for?

While Pizza Hut has consistently been the strongest performer in the U.S., according to the company's annual report, Taco Bell's new product and extended hours are helping offset the poor domestic performance of Yum's fried-chicken-loving​ KFC.

Chicken and biscuits haven't completely lost their edge, though. Americans may seem to shrug off the snacks, but consumers in emerging and foreign markets are eating them up -- or Yum is at least trying to make them.

KFC has more than 3,700 restaurants in more than 700 cities throughout China, along with locations in India, Russia, France, Germany and some countries in Africa. And while the slowdown in China took away the appeal of such a global presence in recent quarters, the company hopes its foothold in the market will pay off in the long run.

For the short term, though, Yum is following the old motto "If it ain't broke, don't fix it." The company plans to keep betting on the super-popular tacos and is already testing a chile-lime version in Toledo.

The product may help Yum continue to compete with momentum stock Chipotle Mexican Grill (CMG), along with the big three of McDonald's (MCD), Wendy's (WEN) and Burger King (BKW).

It remains to be seen whether KFC will turn things around abroad and at home, or whether fried chicken is close to kicking the bucket. But for now, Yum's youngest child is doing its part to support the family.

So far this year, the stock has seen solid 9% gains.

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