Breakfast is increasingly the restaurant meal to watch although analysts say entering the space is no slam dunk.
"I think it's a pretty difficult meal period," said Bob Goldin, executive vice president at food industry consultancy Technomic, adding that "there's been more failure out there than successes" for brands looking to break into the space.
Still, restaurant chains are ramping up offerings within the space since breakfast has shown the strongest growth of any time of day. Currently, it accounts for roughly a fifth of visits in an industry plagued by dropping traffic.
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Enthusiasm for expanding breakfast is especially pronounced among chains that already have a widespread footprint in the U.S., such as Yum Brands' Taco Bell, which recently said it would launch breakfast nationwide, and Chick-fil-A, which is testing new items in some select markets.
In the wake of Taco Bell's announcement, both Starbucks and Dunkin' have expanded their breakfast sandwich offerings. Meanwhile, McDonald's CEO Don Thompson mentioned to analysts that it is increasing focus on breakfast by "creating more of a coffee culture" since coffee drives visits at breakfast.
The ultimate goal for restaurants is inserting themselves into customers' daily morning schedules, said Peter Saleh, a director and senior restaurant analyst at Telsey Advisory Group. He described the breakfast eater in Wall Street parlance as an "annuity"—a customer who's "dependable and consistent."
"The breakfast customer tends to be pretty loyal," he added. "They don't change their routine. They usually do the same thing every day."
Challenges for the breakfast club
But the loyalty aspect is a double-edged sword for restaurants, who can find it tough to alter these routines, Saleh said.
"The economics are tough for breakfast if you're not already open. The franchisees have to bring in labor and different food," he said.
The meal's typically lower price tag presents another headwind as chains must generate strong traffic to surpass expenses.
Still, many companies have piled into the arena lately—with innovation and promotions coming at the expense of dinner and lunch.
Promotions for new and limited-time breakfast items surged 70 percent for the first two months of the year, compared to the year-ago period, according to Technomic. During the same period, lunch and dinner promotions dropped nearly 13 percent. (Although it's worth noting that the number of lunch/dinner promotions dwarfs those of breakfast by a ratio of roughly 10 to 1.)
Boycotting breakfast—for now
Not every chain is looking to breakfast to boost sales.
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Following a test of breakfast items at some airport locations, Chipotle decided against continuing the expanded offerings. Chris Arnold, Chipotle's communications director, wrote in an email that "breakfast is not a priority to us at this time."
"What we find is that our customers prefer their usual order (even in the morning) and have discontinued those tests," he added.
Noodles & Co. has also decided against breakfast for now after mulling the idea over, said its CEO and Chairman Kevin Reddy in an interview.
"We don't have that on the horizon in the near term, and that's because we think there's still opportunity to continue to grow the business at lunch and at dinner," he said. "We think it's better to stay focused on those initiatives and optimizing them before we add the complexities of a breakfast."
—By CNBC's Katie Little. Follow her on Twitter @KatieLittle.