Animal Farm: Thoughts on Orwell's use of animals as characters

This is just my opinion, so people may disagree or see differently than I do, which is awesome.

George Orwell's Animal Farm is a very thought provoking story of the fictional revolution of animals on a farm. George Orwell uses animals as the characters in his story instead of humans, which I thought was odd when I first began to read this story.

This use of animals is effective in helping me to understand how this society is similar to a utopia/dystopia. In my mind, the different animals of Animal Farm are similar to people born with different characteristics such as Boxer seeming to be born into manuel labor and the pigs being more clever and smarter by who they are (as in pigs). Animal Farm is a parallel (is that the right word?) to Joseph Stalin's Soviet Russia during and around World War 2. The animals other than the pigs and dogs can be compared to the proletariat of Soviet Russia during that time. The separation of the animals by species greatly helps to represent who they were, such as the sheep and ducks, who were much less intelligent than Boxer. This separation by species seems close to the separation by a different kind of person/people. This is somewhat hard to describe unless you know what I'm thinking or talking about.