First of all, this is not a cartoon for young children. I can see it being shown for a History or social studies class for middle or high school. It's not meant to be strictly for entertainment, but was okay.
Here's what happens: the animals of a farm unite and overthrow their farmer/master, who is a drunk loser. The animals agree to have an autonomous commune and live in peace working together. The pigs, who are legitimately the most intelligent and human-like of the group, start using their intelligence to their own advantage. They take control, and eventually move into the farmhouse, becoming more human-like as the days go on. Eventually the animals realize that the pigs are no better than the farmer they kicked out!
The movie is an allegory to communism/socialism or something. I didn't read the book in school and I don't intend to now. I feel really bad for Boxer the horse. He worked so hard to help everyone, and when he was injured, instead of calling the veterinarian, the pigs sold him to a glue factory. That is hardcore cold.
What did I learn? The communist system cannot work because some people are naturally leaders and others followers. People with more ambition and intelligence can use this to their advantage against other people. For example, I spent 15 minutes today explaining to a client that the second floor is above the first floor. Some people are corrupt and want power and can hurt people to gain this (like the pigs who take control of everything). This film has some interesting concepts, and it's decently drawn. So I'll give it a 6/10.