Throughout Animal Farm, we’ve seen the pigs betray the principles of the Rebellion over and over again. Yet no betrayal is quite so poignant as what happens after Boxer’s lung collapses. Squealer tells everyone that Boxer is going to be taken to a veterinary hospital in Willingdon for surgery.
When the animals go to see Boxer off, Benjamin the donkey appears and starts crying that they are all idiots. He reads the side of the van to them: "Horse Slaughterer and Glue Boiler" (9.19). All of the animals shout to Boxer that he must kick his way out, and he tries, but old and weak as he is, he cannot.
A few days later, Squealer comes back and explains the "misunderstanding." He says the surgeon purchased the van from the horse slaughterer, but that he has not yet changed the name. Squealer claims that they did everything they could to save Boxer. Napoleon holds the horse a memorial service, and ends it by reminding everyone of Boxer’s two favorite maxims: "I will work harder" and "Comrade Napoleon is always right" (9.29).
Boxer, in many ways, is an example of the perfect proletarian (worker). He never complains; he is extremely loyal; and he literally works himself to death. Yet his reward is that he is sold off, slaughtered, and turned into glue. Meanwhile, the pigs are living lavish lifestyles in the farmhouse and getting drunk off cartons of whiskey.
Though the betrayal of Boxer is not a link to any specific episode in Russian history, it might be seen as a brief ‘allegory within an allegory’ for Stalinism as a whole. And, in a way, Orwell’s imagery is all too literal. As the van rapidly moves down the road with Boxer trapped inside, one can’t help but think of so many victims of the Stalinist regime that were made to disappear or were sent to Gulag concentration camps.