What are Orwell's major concerns in Animal Farm?

Simply put, Boxer is Orwell's major concern in his work. 
The idea of the loyal subject, an individual whose only concern is "to work harder" is
of significant concern to Orwell.  The fact that Boxer strives to "work harder" and then
is "rewarded" for his efforts with a sale to the glue factory, sealing his doom is
something that Orwell sees as representative of the future in terms of the relationship
between government and governed.  Naturally, Animal Farm is a
representation of the Soviet Union.  Yet, there is a larger concern for Orwell in the
way in which individuals place trust in their government.  The idea of blind faith and
loyalty, along with the refusal to question authority is something that concerns
Orwell.  The idea that individuals can be sheep, literally and figuratively, causes
significant worry in Orwell.  The ending of the book where the animals literally cannot
tell the difference between humans and pigs is something that Orwell feels lies at the
heart of all political orders that believe they are able to manipulate the will and
heart of the people.  In order to avoid this state of affairs, Orwell demands a sense of
questioning and accountability between people and their
government.