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Craving a McDonald's lobster roll? More than likely, you're out of luck at your local McD's joint. In fact, there's a good chance you have never even heard about it.

All-day breakfast isn't the only idea fast food giant McDonald's is limiting to a select group of restaurants.

Depending on which of the country's more than 14,000 locations customers visit, they could see everything from buttermilk crispy chicken to bundt cakes on the menu at the chain's corporate and franchised branches.

When a restaurant is as big as the Golden Arches, it can't just hope a new item or feature like all-day breakfast works out. McDonald's uses small tests—like a current one with all-day breakfast in select San Diego-area restaurants—to see whether a new item has potential to be a hit or a flop.

The company also has a number of regional menu items meant to cater to local market preferences. As part of its turnaround efforts, McDonald's has pledged to localize its menu and marketing efforts to be more relevant to regional tastes.

Click ahead to see some of McDonald's most exclusive menu items.

—By CNBC's Katie Little
Updated 30 July 2015

Scott Mlyn | CNBC