"The dissident campaign has not made a sufficient case, on an issue-specific or broader view of ESG, that the immediate replacement of incumbent directors is necessary at this time," ISS wrote in the report it sent to clients on Monday morning.

Icahn is trying to convince shareholders to add his director nominees to the board to hold the company accountable to pledges it made a decade ago to stop buying pork from producers that use gestation crates.

(Reporting by Svea Herbst-Bayliss)