Burger chain Shake Shack eyeing chicken

Long known for its burgers, Shake Shack is turning an eye toward chicken, according to one recent trademark filing.

A subsidiary of the company called "SSE IP" on April 20 filed an application for "chicken shack," detailed on the filing only as pertaining to chicken sandwiches. Shake Shack was mum on the details, but companies often file applications before announcing new items or initiatives.

"Shake Shack was born from a fine dining company, and we constantly test new menu items in our test kitchen," according to a statement from the company. "We have no new items to announce at this time, except for the new ParkBurger at New York's Madison Square Park, which reopened today."

Currently, the only menu item featuring chicken is the chicken dog, a hot dog made with chicken, apple and sage sausage.

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If the application does signal more chicken is on the way, it would increase menu diversification at the chain—not to mention tap into a faster growing segment than burgers in fast food.

Chicken entrees grew 3 percent to $5.4 billion for the year ending in March at fast-food restaurants at a quicker clip than burger servings, which ticked 1 percent higher to 7.9 billion, according to market research firm The NPD Group.