Manor Farm's farmer Mr Jones is human. His livestock, animals. The cows are milked, the chickens lay eggs, the fields provide hay. Mr Jones takes it all. The animal have had enough, and decide to revolt!
Mr Jones is chased off of the farm, leaving the animals to run the show. Manor Farm becomes Animal Farm. A new ideal, a new order settles. Animals will work shorter hours, feed won't be rationed, new animal specific retirement ages are set and land reserved for retirement purposes. The intelligent animals have learnt to read and write and under Snowball's leadership (Snowball is a pig) new laws are passed to ensure the peace at Animal Farm lasts.
The animals work the farm more efficiently than Mr Jones had. Living standards are up. The news of the revolution spreads to nearby farms, the humans become restless. They try to reclaim the farm but the animals are prepared and defend the attack. Medals are bestowed on the brave, legends are formed. The flag (a horn and a hoof upon the backdrop of the green countryside of England) is flown to rejoice in the victory.
Jealousies and personal ambition simmer, the pigs splinter into two groups, Napolean and his followers vs Snowball. Snowball is exiled and slowly becomes the anti-hero. The legend of Snowball the brave, the courageous, becomes Snowball the traitor, in leagues with the humans to bring about the fall of Animal Farm. Snowball is never seen again, however every misfortune, every lost crop, every negative outcome is broadcast, and believed, as Snowball's doing. The animals become afraid of the sinister Snowball, who legend has it, ghostlike roams the farm creating mischief and mayhem.
Rations are reduced, working hours get longer. The pigs, of course, now require the all the milk for their brain power. They make contracts with the humans to sell the eggs to fund the mechanical part of the windmill. Utopia becomes dystopia. The rules, written on the barn wall, seem to be changing one by one, but only a few of the animals can read and even so they are told the rules have always said that. Some animals are accused of treachery, and slaughtered. The pigs move into the farm house, drink the beer, dress up in Mr Jones' clothes. The animals aren't equal, the corrupt pigs run a dictatorship. The retirement age disappears, the retirement paddock instead used to grow hops for more beer... Slowly as the pigs form relationships with the neighbouring humans, the mantra of 'four legs is good, two legs is bad' becomes 'four legs is good, two legs are better' until one haunting morning the pigs parade around the farm walking on their hind legs. The transformation is complete. They in actions, mannerisms and thoughts have become the humans they so vehemently despised and rebelled against.