What are some examples of the installation of fear in Animal Farm?

I would say that Napoleon's brutality in Chapter 7 goes
very far in displaying a government that installs fear as a primary motivator.  The
forced confessions and the brutality that results is fairly horrific and is one where
the animals might wish to rebel, but would dare not articulate it.  This point in the
text is a telling reminder of how Napoleon's government has to install fear in the mind
of the animals in order to effectively function.  The savagery with which the dogs tear
out the throats of those who publicly admit to going against the government serves as an
example to other animals to not speak out against the Status Quo.  The installation of
fear is accomplished because there are so many other emotions that are ongoing within
the animals who must witness such a display of power.  For example, Clover is unable to
speak because she experiences so much confusion about what she is seeing.  There is
repulsion and anger, betrayal and hurt, but above all, there is fear that keeps her
voice silent, and something that the government of the pigs has to employ in order to
consolidate their own power and control.