In Animal Farm, George Orwell lets the narrative itself convey his message on the dangers of totalitarianism and populist uprisings. Orwell did not need to explain the motives of the characters, because we the characters—particularly the pigs—transform into human-like creatures.
Orwell uses irony by illustrating the "evolution" of the pigs—especially Napoleon and Squealer—from disgruntled abused animals to becoming abusers themselves. For instance, Orwell frames this evolution by showing the negative traits of men. Orwell depicts the farmers as drunk, abusive, and lazy. The humans represent the old aristocratic regime which did not care about the welfare of their subjects. The animals, at the beginning of the story, represented the oppressed citizens of monarchies. The Battle of the Cowshed is similar to the civil wars and revolutions of men throughout history. The act of going to war itself showed that the animals were becoming human-like.
In the middle of the story, Napoleon began to exhibit negative traits of people: greed, sociopathy, and vengeance. Likewise, Squealer began to lie to the other animals, an act which represented the spread of propaganda in the real world. The act of lying is a human trait. These are some of the examples of the pigs' transformation. Even Snowball showed human characteristics, such as having progressive ideas and believing in infrastructure.
By the end of the novella, the pigs are wearing human clothing and carrying whips to punish the other animals. This final scene is the ultimate illustration of Orwell's use of irony in Animal Farm.