Propaganda is used in several ways. The first example is the song "Beasts of England," which is spread around the farm and even to other farms; this song motivates the animals to think about revolution, and to fight a specified enemy -- humans -- even though their lives are not all that bad. Later, as Napoleon begins to take control, he uses Squealer to justify all his decisions. Squealer is good with language and good at excusing behavior by the pigs that would be criminal from other animals:
He assured them that the resolution against engaging in trade and using money had never been passed, or even suggested.... "Are you certain that this is not something that you have dreamed, comrades? Have you any record of such a resolution? Is it written down anywhere?"
(Orwell, Animal Farm, msxnet.org)
This is an example of propaganda created by the "government," or by Napoleon's regime. By controlling the topics and themes of discussion, and by vilifying and distracting, Squealer prevents the animals from questioning Napoleon and showing the flaws in his leadership. Squealer's voice is echoed in a vague sense by the sheep, who repeat the mantra "Four legs good, two legs bad" without any actual understanding of its meaning, and without understanding the issues at hand. This shows the tendency of news organizations and private citizens to parrot what they hear without looking for deeper truth; this is an example of "unintentional propaganda."
As a persuasive technique in politics, propaganda is the transmission of information that is specifically geared towards convincing people to believe in one doctrine, belief system, religion, political party, and any other philosophy that requires convincing a big population.
In Animal Farm, the animals use the propaganda in many ways to persuade all the other animals that they should harbor hatred against humans. One of the ways is by memorizing the motto: "Four legs good, two legs bad"
Another instance of propaganda that is clear is the support of the theory of "Animalism". As a philosophy, the leader animals created this doctrine to convince the other animals of the importance of putting themselves first, and the humans later.
There are many more instances of propaganda in the story that could fill up a dissertation, but keep in mind that every time the animals, Old Major, Napoleon or any other of the big guys throw information towards the lesser animals against the humans, or against something else, that would be an instance of propaganda in the story.
Propaganda is satirized through Squealer the pig. He symbolizes Stalin and the government's control over all media and information being given to the peasants. Because they were uneducated, the peasants could not follow twisted or illogical arguments when they were presented by someone whom they respected and considered intelligent. Furthermore, just like in Soviet Russia, the people had once trusted the government's intentions, so they trust the pigs and Squealer, and don't want to seem ungrateful or confrontation by questioning things that confuse them (especially because they know they don't have to the ability to argue back).
First, a definition, propaganda is "the spreading of ideas, information, or rumor for the purpose of helping or injuring an institution, a cause, or a person."
In short, the propaganda emerges after the animal revolt which deposes the Mr. Jones and installs Napoleon and company as rulers. The propaganda in the text comes from the pigs and is disseminated to the other animals formally through both the "Beasts of England" song and "The Seven Commandments."
The essential function of all the propaganda in the text is to legitimize the pigs' autority and increase their power. It is notable that while the Commandments apply to all animals, the pigs themselves break every one of them, while expecting the other creatures of the barnyard to continue their obedience.