If you are discussing the classic cartoon - the John Halas and Joy Batchelor film, produced by de Rochemont Films, bear in mind when considering whether it faithfully replicates the meaning of the Goerge Orwell book, that is now proven that it was substantially funded by the CIA as anti-soviet propaganda.

Enquiries as to US rights should be directed to Shaler McReel at the current de Rochemont corporation called de Rochemont Films Inc.

Enquiries as to non-US rights should be directed to Joe D'Morais, at Blue Dolphin Films Ltd, London, who AFAIK still represent the Halas and Batchelor Collection Ltd.

There is a research archive on Halas and Batchelor material generally at an academic institution in Surrey but Shaler McReel has a quantity of Animal Farm-specific material.