Once a week, Arty Schronce, an employee at the department, calls facility managers, who give him information including how many birds were processed each minute on how many production lines and over what number of shifts, and the average price per pound of poultry sold. Mr. Schronce enters the figures into a formula used to calculate the price of a 2½- to 3½-pound bird, as well as prices for parts of chickens. The price is published once a week on the department’s website.

But critics say the index does not do enough to verify the data it receives. They also say the two largest producers in the state, Pilgrim’s Pride and Tyson Foods, hold too much sway over the index. The prices supplied by the largest producers are weighted more heavily by the index than the prices from other producers.

The Agriculture Department had long included the Georgia Dock in a weekly report on poultry production and prices. But in the spring, it began asking questions about how the index was compiled, according to emails between federal and state officials. The documents, which were obtained through a Freedom of Information request, were provided independently to The New York Times and authenticated by the agency.

In the summer, the department told Mr. Schronce that to remain on the weekly report, the Georgia Dock needed to start verifying the prices producers were giving them, among other changes.

But in a later email sent to Gary Black, Georgia’s agriculture commissioner, the Georgia department conceded that it could not verify the numbers it had been using to compile the Georgia Dock. And it said the department “is in agreement with the poultry industry that there is no desire to review invoices for verification of data reported.”

In August, the United States Department of Agriculture dropped the Georgia Dock from its weekly report and now provides only a link to its website.