By Chapter 10, the final chapter in Animal Farm, the majority of animals have become so brainwashed by Squealer's propaganda that they essentially have lost touch with all memory of what Animal Farm was supposed to be all about. Most of the animals who participated in the initial uprising, in fact, are dead. The few objections that the animals raise when they see the pigs walking around on two legs are drowned out by the sheep, who bleat out "Four legs good! Two legs better!" Even Clover, who remembers the early days of the revolution, doesn't offer a protest when it becomes evident that the animals have winnowed the Seven Commandments down to one:
ALL ANIMALS ARE EQUAL BUT SOME ANIMALS ARE MORE EQUAL THAN OTHERS.
By the end of the book, the pigs have even taken on the physical characteristics of humans, but by this point, the animals of the farm have become so throughly indoctrinated that they experience only a vague sense of confusion and sadness.