McDonald's chicken wings? Testing expands.

First there were McNuggets. Then there were Chicken McBites. Now McDonald's could be adding "MightyWings" to its chicken menu.

The world's biggest hamburger chain is set to expand its test of McDonald's chicken wings to Chicago this week, after a successful run in Atlanta last year. The wings are expected to be sold in three, five or 10 pieces with prices likely starting at $3, according to Lynne Collier, an analyst with Sterne Agee.

A spokeswoman for McDonald's confirmed the test in Chicago would start this week but said there weren't any plans yet to bring the wings to other cities. Fast-food chains typically test items in select markets before taking them national. But 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 percent 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.

And prices could continue to climb with demand remaining high.

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. But 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.

The 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. But 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. And last week, the Miami-based chain even introduced chicken nuggets that more closely resemble McNuggets, replacing the chicken tenders it previously sold.

In addition, McDonald's is facing competition from newer chains such as Chipotle Mexican Grill Inc. and Panera Bread Co., which serve higher-quality food for slightly higher prices. In October, McDonald's said a key sales figure dropped for the first time in nearly a decade. The figure rebounded in November after McDonald's said it would return to emphasizing its Dollar Menu to lure price-conscious diners.