Fried-chicken chain KFC would like to advertise its breaded tenders on television but is opting not to because there’s still not enough chicken, especially of the boneless variety, to go around.

“On chicken tenders, we have enough to supply demand, but we would love to have more to be able to aggressively promote it on TV,” KFC U.S. President Kevin Hochman said in an interview. “In terms of advertising and promotion we’re going to focus on things we have abundant quantities of,” he said, noting that bone-in chicken is more plentiful now.

Americans are flocking to boneless chicken sandwiches. Rivals capitalizing on the trend include Popeyes, Burger King and McDonald’s Corp., which earlier this year said its new crispy poultry sandwich was exceeding expectations in the U.S. But a shortage of workers across the supply chain—especially in poultry plants—is making it tough for companies to keep grocery shelves and restaurants fully stocked.

Chicken tenders and similar items, such as nuggets, require extra processing to remove the meat from the bones.

“That tends to have little bit more labor required,” Hochman said, noting that poultry supply for Yum! Brands Inc.-owned KFC is improving week by week.