In the beginning, one of the mottos accepted by the animals was, "Four legs good, two legs bad!" In the end, that motto got changed to, "Four legs good, two legs better!"
One of the Commandments originally was, "All animals are equal!" That got changed to, "All animals are equal, but some are more equal than others."
One given by Old Major in the beginning, was "All men are enemies. All animals are comrades." Another one he gave was: "Whatever goes upon two legs is an enemy. Whatever goes on four legs, or has wings, is a friend."