McMuffins for lunch? McDonald's flirts with all-day breakfast menu.

McDonald's will begin testing an all-day breakfast menu at select locations, according to reports. The move to bring McMuffins and McGriddles to lunchtime comes as McDonald's fights to win back customers and fend off challengers like Taco Bell in the coveted fast food breakfast market.

McMuffins for lunch at noon? Hash browns for an afternoon snack at 3? All-day breakfast may be coming to a McDonald's near you.

The fast food giant is planning to test an all-day breakfast menu in select locations within the next month or two, according to reports from Janney Capital Markets.

Testing 24/7 breakfast "makes sense" Janney Capital Markets analyst Mark Kalinowski told Business Insider, noting that some of the most "craveable" items on the McDonald's menu are the McMuffins and McGriddles. "We believe customers generally want to see McDonald's offer breakfast items all day."

It's a big change for the fast food chain, which usually stops serving breakfast at 10:30 a.m. on weekdays and 11 a.m. on weekends. 

The reason why: McDonald's prepares breakfast items like eggs and sausages on its grills, and in most McDonald's restaurants, its grills aren't big enough to handle both breakfast and lunch items.

"It comes down to the sheer size of kitchen grills," McDonald's wrote on its website. "They simply don't have the room for all of our menu options at one time — especially considering we use our grill to prepare many items on our breakfast menu." 

Typically, the grills and toasters are used for breakfast items until 10:30, before workers start using the equipment for burgers and sandwich buns for the lunch rush.

As such, the all-day breakfast menu may pose a significant logistical challenge for the fast food giant. McDonald's is testing the idea in a limited number of locations to work out the kinks before deciding whether to roll out it nationally.

So why is it taking a risk and testing out the concept?

For starters, McDonald's is facing a lot of new competition on the breakfast front. Taco Bell launched a breakfast menu last year, and Starbucks, Dunkin' Donuts, and Subway have also taken large wedges of market share from the fast food breakfast pie, which McDonald's has long dominated.

The company actually pioneered breakfast fast food when it introduced the Egg McMuffin in 1972 - a radical idea at the time. By 1977, McDonald's had added a full breakfast line to its menu, and some ten years after that, one-fourth of all breakfasts eaten out in the US came from McDonald's restaurants.

The company isn't happy to surrender that control to more recent entrants in the breakfast market.

And under new CEO Steve Easterbrook, the chain is testing a number of new initiatives to win back customers after several quarters of disappointing sales. Among them is a focus on healthy, high-quality ingredients, and on breakfast as a key area for growth. The chain has heavily promoted its coffee and has emphasized in recent advertising that it uses eggs cracked in the kitchen, not pre-cooked egg substitutes.

It may also be heeding a recent National Restaurant Association survey that found nearly 70 percent of Americans want breakfast available all day, and that younger adults love eating breakfast for dinner.

If McDonald's test run is successful, Americans can order breakfast alongside their burgers, all day long.