The Second Circuit U.S. Court of Appeals has upheld the dismissal of a securities fraud class action against Sanderson Farms Inc., finding that investors had not adequately supported allegations that the company conspired with other chicken producers to control supplies and drive up prices.

The ruling Tuesday, from a unanimous panel, was a win for Mississippi-based Sanderson Farms, the country's third-largest poultry producer, and its Kirkland & Ellis attorneys, who succeeded in having the lawsuit dismissed last year.

Sanderson Farms investors Gordon Gamm and Don Pritchard had alleged in the complaint that the agribusiness failed to disclose a secret plot to manipulate natural "boom and bust" cycles in the chicken market to capitalize on high prices.