A spokeswoman for McDonald's confirmed the test in Chicago would start this week at about 500 restaurants but said there were not any plans yet to bring the wings to other cities. She noted that no new sauces were being offered with the wings and that the creamy ranch sauce would be the default dipping sauce.

Fast-food chains typically test items in select markets before taking them national. However, for McDonald's, which has 14,000 U.S. locations, adding chicken wings to the permanent lineup could be tricky.

Prices for chicken wings have been climbing over the past year, reflecting an increase in the number of restaurants serving them, said David Harvey, an agriculture economist who specializes in poultry and eggs at the U.S. Department of Agriculture. In December, the cost of wings in the wholesale market in the Northeast was 26% higher than a year ago. Wings sold for $1.90 a pound that month, compared with $1.30 a pound for boneless, skinless chicken breasts.

Prices could continue to climb with demand remaining high, pressuring prices for wings across the industry.

Rather than becoming a permanent part of the menu, McDonald's could offer the dish for a limited time; the chain has said it plans to ramp up the frequency of such special offers as a way to give customers more variety. However, whether it will offer "Mighty Wings" even on a limited-time basis will likely depend on McDonald's ability to get wings at reasonable prices, said Collier, the analyst with Sterne Agee.

There could be other challenges. Richard Adams, a former McDonald's franchisee who now runs a consulting firm for franchisees, said that menu items generally do not work unless they can be eaten easily in the car. He noted that the majority of McDonald's food is purchased at the drive-thru.

This is not the first time McDonald's is offering wings, however. According to the National Chicken Council, McDonald's first introduced them in 1990 at some locations, prompting other fast-food chains to follow suit. A McDonald's representative was not able to immediately provide the history of "Mighty Wings."

The latest test comes amid intensifying competition for McDonald's, which for years had outperformed rivals such as Burger King and Wendy's with a steady stream of new menu items, such as snack wraps, fruit smoothies and specialty coffee drinks. However, now Burger King and Wendy's are working to revamp their images and menus.

This past spring, Burger King launched its biggest ever menu expansion to include its own snack wraps, fruit smoothies and specialty coffee drinks. Recently, the Miami-based chain even introduced chicken nuggets that more closely resemble McNuggets, replacing the chicken tenders it previously sold.