What was the purose of the ten commandments of "Animalism," and how were they altered by the pigs?

Animalism was created by the animals in purpose of the
Rebellion. Then ten commandments was the law of Animalism, and all animals had to follow
those rules no matter what.

However, as the need for
products (that could not be grown on the farm) increased, the pigs soon started
communicating with humans in order to get these products, mainly beer, as the pigs and
dogs got addicted to it. Contact and interaction with the humans influenced the pigs,
who then began to walk on two legs, wore clothes, and drank
alcohol.

Since they were breaking the law by doing all
these things, they secretly gave themselves permssion to alter the ten commandments so
that it seemed that they wouldn't be breaking the rules.