Orwell is using the analogy of the farm and the roles of the different animals, which change as the pigs take control, as his indictment of totalitarian governments. Orwell was bitterly disappointed that the Russian Revolution of 1917, which ousted the tzarist regime and claimed to be the beginning of a government run by and for the people, evolved into a government concentrating total power in the hands of a very small group of autocrats.
Animal Farm presents Orwell's vision and condemnation of the Revolution. The tsar, represented by Mr. Jones, is ousted. At first all the animals, standing for all the different groups and classes of peasants, industrial workers, and organizers of the revolt, work together to create a new and better system. As time goes by, certain groups begin to assign themselves privileges and powers that had been held by all. In the end, the majority of the animals are worse off than before the revolution, suppressed and completely controlled by the minority that benefits from all their labor.