The pizza delivery chain pledged to source its grilled chicken products and chicken poppers from animals that have been raised without antibiotics. According to the company’s press release, Papa Johns’ suppliers have also agreed to feed the poultry a fully vegetarian diet.

The release did not mention other chicken menu items, but Sean Muldoon, Papa John’s senior vice president of of R&D, quality assurance, and supply chain, tells Fortune that the company is in the process of making its wings antibiotic-free as well, but “there are complexities that make the timeline longer.” As for grilled chicken toppings and chicken poppers, the switch will be rolled out to all of Papa John’s U.S. locations by the summer of 2016.

A report, obtained by Consumerist, was released in September by a coalition that included the Natural Resources Defense Council and the Center for Food Safety rating restaurant chains based on their antibiotics policies. Papa John’s was given an “F.”

Although the press release states that Papa John’s is the first national pizza chain to make this move, it’s just the latest U.S. chain to make the antibiotic-free pledge following in the footsteps of Subway, McDonald’s (MCD), and Chipotle (CMG).