What are some specific examples of metaphors in Animal Farm?

I would say that the characters in the book are the best
examples of metaphors. Under the pain of censorship and not being published, Orwell had
to construct the animals as extended metaphors of the historical figures he satirized. 
For example, Benjamin is a metaphor for the disaffected and cynical intellectual who
realizes too late the need to take action.  In this, Benjamin is a metaphor for the
likes of the Orwells of the world who realize far too late that their call to action has
in fact passed.  Orwell looked for a way to bring out the loyalty of those who followed
the revolution in Russia and paid the ultimate price for it.  In this, I think that
Boxer is a wonderful metaphor. He represents how individuals who pledge unquestionable
loyalty to a government can end up being sacrificed for it.  I think that the metaphor
for the misguided individuals who are trapped in between how political reality is going
and how it should be going would be seen in Mollie, who never really has the courage to
launch a counter- revolution but has extreme difficulty in being able to identify how
what is happening on the farm is in line with what was initially promised.  Orwell uses
his characters as metaphors, a way to draw out the comparison between what he wishes to
say and how he can say it.