"For whatever reason, they just didn't gain quite as well this year," he said.
Like many other turkey producers, Butterball feeds its birds antibiotics to prevent and treat illnesses, which can occur from living in cramped quarters. The use of antibiotics, which also promote growth in livestock, has been the subject of concern that it could lead to antibiotic-resistant germs.
Butterball, a privately held company based in Garner, N.C., declined to say whether it made any changes to its feed formula this year. But the problem seems to have come up rather recently.
For much of the year, Butterball produces turkeys that are frozen and stored until they're ready to be sold for the holidays. But then in October and November, it shifts into production for fresh turkeys. And that's when the company ran into problems with the turkeys not gaining enough weight, Brenneman said.
It hasn't been an issue for some other poultry producers.