This quote from Animal Farm that "all animals are equal but some are more equal than others" presents a grim picture of life such as it continues to perpetuate, even today.
Propaganda is a tool used to persuade, manipulate and convince people - or in this case- animals to accept biased and misleading information and practices in the interests of a select group - the pigs. It is used throughout Animal Farm to ensure the pigs' domination of the other animals and the successful implementation of their ever-changing commandments.
Napoleon knows that Snowball has every chance of successfully leading the animals and so cleverly ensures that he is chased off the farm. He is then able to use Snowball as a scapegoat, accusing him of sabotage and trying to turn the "hero" of the Battle of the Cowshed into a villain.
Constant references to the possibility of Jones returning to take over the farm are used to keep the animals in line because at least this way they are "free" working for their own benefit " and not for a pack of idle, thieving human beings."
The commandments are regularly changed to suit the pigs' improving lifestyles. The executions of some of Snowball's co-conspirators - supposedly - scares the animals but yet another commandment reads differently than they remember - “No animal shall kill another animal...... without cause.” Furthermore, the pigs amend the fifth commandment to allow for their drinking as long as it is not " to excess.”
Life becomes increasingly difficult for the animals and they are even expected to step aside for Napoleon their "Leader," president of the new republic! The pigs, having established themselves as the "brains" early in the story are now clearly superior to the others.
The ultimate betrayal and disintegration of the ideals of animalism comes with Napoleon's increasingly human mannerisms, supported by the sheep, bleating “Four legs good, two legs better!” The animals are just not strong enough to compete and any thoughts of protest disappear. Benjamin and Clover see the only remaining commandment. The humans return to negotiations and the animals are left bemused and unable to recognize or distinguish man from animal.