Mr.Jones got drunk and didn't feed the animals and they had enough of it so the cows had kicked down the stall and they drove the farmer off of the farm and then they broke into the food stock.
Napoleon gained control over the animal farm by banishing Snowball. And Using the dogs he had to terrify the animals and force them into obeying him and without Snowball around anymore, Napoleon became the leader of animal farm.
The animals are being worked hard every day through night given the same if not fewer rations to eat and are to abide by 7 commandments that are hypocritical. The last sentence from the book can explain it all for me. "The creatures outside looked from pig to man, and from man to pig, and from pig to man again, but already it was impossible to say which was which."