Mr. Jones is a drunken farmer who doesn't take care of his animals, so the animals are planning a revolution to take him down and right now the animals are singing their theme song.
The animals are executing the rebellion and chasing Mr. Jones off the farm. They are doing this because they want to govern themselves because they think they can do it better.
The Farmers are trying to take the farm back from the animals who have taken it over. Although, the animals have a plan to defeat them with strategy.
Napoleon ordered the dogs that he took in while they were pups to chase Snowball off the farm. A little bit after that happened, Napoleon order for the windmill to be built but when they were halfway done, the windmill got destroyed by a storm.
First what happened is that the men poured explosives down a hole next to the windmill to blow it up. Then the animals try to fight back and they make the men retreat and they consider this battle a victory. After that, Boxer gets hurt and Napoleon arranges a horse slaughterer to take him away for money.
The pigs start to walk and wear clothes just like the humans who ran the farm did, and that is what they swore never to do, also they change the seven commandments just to some animals are more equal than others. The animals are frightened by that. The pigs also change the name back to Manor farm and they have basically became humans.