The animals on Manor Farm take over, vowing to forbid any contact with humans, whom they see as immoral enslavers. However, as the story progresses it is very obvious that the virtues that started the revolution have been perverted.
The book is largely a satire of the Russian Revolution. The pig, Old Major, who first comes up with the idea of Animalism, is based on Karl Marx. Snowball the pig, an early leader of the revolution before he is accused of treason and driven into exile, is based on Leon Trotsky. The pig Napoleon who takes over the farm, lives in luxury and imposes his will on all the animals through fear and intimidation, is based on the Soviet dictator Josef Stalin. Boxer the horse represents the workers of Russia.
Animal Farm tells the story of the animals of Manor Farm who have been mistreated by the farmer Mr. Jones, They begin to see hope for a brighter future when, shortly before he dies, one of the oldest animals, the pig Old Major, prophesies the overthrow of the human race and freedom for animals.
The alcoholic Mr. Jones repeatedly fails to feed the animals. The animals refuse to accept this any longer and one morning after Jones sleeps in with a hangover, they break into the food shed and gorge themselves. Mr. Jones and his men attempt to intervene, but the angry animals drive them away from the farm. The animals proceeded to destroy almost everything that reminds them of the humans such as whips, knives, horse bits, leashes. However, the house is left unchanged. It is decided that no animal is to live in the house and it is to be kept as a museum. The animals change the farm's name from Manor Farm to Animal Farm.
A set of laws, called the Seven Commandments, are set up which all the residents of Animal Farm have to follow. They are: .
- Whatever goes upon two legs is an enemy.
- Whatever goes upon four legs, or has wings, is a “friend”.
- No animal shall wear clothes.
- No animal shall sleep in a bed.
- No animal shall drink alcohol.
- No animal shall kill any other animal.
- All animals are equal.
The commandments are painted on the side of the barn in giant white letters so they can be read from a good distance. Most of the animals have poor memories or can't read, which is why the pig Snowball summarizes the rules as “Four legs good, two legs bad”, which the sheep on the farm immediately adopt as their mantra, bleating it repeatedly during crucial speeches by Snowball.
The pigs, being the most intelligent of the animals, automatically assume leadership. There is a power struggle between two pigs, Snowball and Napoleon. Snowball thinks that in order for the animals’ ideology to thrive it is necessary to start revolutions on other farms and sends the farm's pigeons . Napoleon thinks the residents of Animal Farm should learn to use firearms to strengthen the farm from within.
Mr. Jones and other men come to take back the farm, but Snowball proves to be an expert tactician and defeats the invasion by giving each group of animals a different task to perform during the battle. Several animals are killed in what comes to be called the Battle of Cowshed. After the unsuccessful invasion, the humans come to recognize the animals as the legitimate rulers of Animal Farm.
Snowball proposes the idea of making a windmill, he says that although it will take a lot of effort to make, it will generate electricity for the farm, allowing for more of their work to become automated and allow for more leisure time. Napoleon says that he is opposed to the idea. During a crucial debate to elect a leader of the farm, where Snowball seems poised to win, Napoleon takes the podium and suddenly calls in a vicious troop of dogs he'd been secretly training. They immediately set upon Snowball and chase him off the grounds. Snowball is never seen again. Napoleon denounces Snowball as a traitor and forbids and mention of him from then on. Later, Napoleon accuses more animals of treason and orders them to be executed by the dogs, violating the sixth commandment, “No animal shall kill any other animal”, Napoleon justifies his behavior by saying that the rule has in fact always been, “No animal shall kill any other animal, without cause.” Muriel discovers that this change has been made to the commandment painted on the barn.
Napoleon surprises everyone by announcing that he was in support of windmill construction all along and that Snowball stole the plans from him. The animals begin the laborious task of constructing the windmill. The work is hard, but soon the building begins to take shape. One night, the animals all dream of a gunshot in the distance; they wake up to find their windmill in ruins. Napoleon proclaims that Snowball came in the night and destroyed the windmill. He orders him sentenced to death. However, the humans believe the windmill fell because the walls were too thin and a strong gale toppled it. The animals restart construction and make the walls three feet thick instead of eighteen inches thick, making the new project even more labor intensive.
Napoleon announces they will sell some lumber to the farmer Mr. Frederick in order to raise money. The transactions go smoothly until the animals find out that Mr. Frederick is using counterfeit money to pay them. Napoleon sentences Mr. Frederick to death. Mr. Frederick and some other men come to invade Animal Farm; the animals fight fiercely but can not keep the humans away. Napoleon sends a pigeon to request help from the farmer Mr. Pilkington, but in reply Pilkington simply says “Serves you right”. The men come with explosives to blow up the windmill. Enraged at the destruction of the windmill, the animals attack and Frederick's men retreat, but they suffer many casualties. Napoleon announces that they will rebuild the windmill yet again, this time as more of a symbol of victory than as a practical piece of machinery.
Most of the animals from the days of the revolution grow old during the intervening years. Several of them, mostly pigs, are permitted to retire. However, the horse Boxer, who is the hardest working of all the animals and one of the most loyal to Napoleon, keeps working despite old age and becomes injured while hauling stone to the windmill site. Napoleon calls for a truck to take him away. Boxer's oldest friend, Benjamin the goat, who can read as well as the pigs, notices that the van that picks Boxer up is a knacker's van and that the horse is being taken to a factory to be slaughtered for glue and dog food. However, Napoleon has his propaganda minister, Squealer, report to the animals that the van belonged to a vet who hadn't changed the van's markings to his own. Squealer tells the mourning animals that he was with Boxer to the moment he died, he was well taken care of and that he'd declared himself still a loyal follower of Napoleon.
Napoleon becomes increasingly human in his behavior and changes the saying “Four legs good, two legs bad” to “Four legs good, two legs better”, which is also a new chant taught to the sheep by Squealer. As proof of his newfound belief, the animals see him and more of the pigs walking on two legs. They are horrified to see Napoleon carrying a whip, a punishment implement that they hadn't seen since the days of Jones and they thought had been abolished.
Eventually, the Seven Commandments are replaced by a single one: "All animals are equal, but some animals are more equal than others."
The last scene in the novel takes place many years later. Most of the animals who were alive at the time of the revolution have died but Napoleon and a few other pigs are still alive. Jones himself has also died in a home for alcoholics somewhere else in England. Napoleon meets with Pilkington and other humans in the house. The pig announces that the farm is to return to its real name of Manor Farm. During a card game, Napoleon and Pilkington simultaneously play an ace of spades, and an argument erupts. The animals look into the house and can not tell pig and human apart.
- Text of George Orwell's Animal Farm on Wikilivres. The site is hosted in South Korea where the novel is in the public domain. It is still under copyright in the United Kingdom and the United States.
- Quotations from and about Animal Farm on Wikiquote.
- Orwell's original preface to Animal Farm.
- Animal Farm on Orwell Wiki.