The main target of this allegory is Stalin, represented by Napoleon the pig. He represents the human frailties of any revolution. Orwell believed that although socialism is a good ideal, it could never be successfully adopted due to uncontrollable sins of human nature. For example, although Napoleon seems at first to be a good leader, he is eventually overcome by greed and soon becomes power-hungry. Of course Stalin did too in Russia, leaving the original equality of socialism behind, giving him all the power and living in luxury while the common pheasant suffered. Orwell explains: “Somehow it seemed as though the farm had grown richer without making the animals themselves any richer - except of course for the pigs and the dogs.” it’s not necessarily the system that is corrupt or faulty, but the individuals in power.
Old Major, with all his good intentions, took no note of the crucial fact that whilst his ideals were sound and moral, corrupt individuals found ways and opportunities to exploit those ideals to fulfill their own purposes. So Orwell successfully points out the frailties of his satirical targets