Benjamin the donkey remains skeptical, and Boxer the horse remains hard working under both farms.  The pigs change because they are in charge.

Most animals remain the same, but the pigs change under the new farm because they are in charge.  For example, Benjamin the donkey is skeptical and ornery under both masters.  Boxer the horse is loyal and hard-working.  These animals do not really care who is in charge.  Things do not really change for them.  To Benjamin, the new boss is just as bad as the old boss.  To Boxer, he will remain loyal and true.

Benjamin seems to know the score.  He talks in strange ways, but he is observant.  He is a good friend to Boxer, but basically also a loner.  He does not speak ill of the pigs’ leadership, but doesn’t support it either.

When asked whether he was not happier now that Jones was gone, he would say only "Donkeys live a long time. None of you has ever seen a dead donkey,"... (Ch. 3)

Boxer, on the other hand, is completely loyal to Napoleon.  He was a good work horse for Jones, but goes the extra mile for the lead pig.  His favorite saying is “Napoleon is always right,” and he is always willing to chip in and work harder.  He never questions anything Napoleon does or says, and works himself into the ground for Napoleon right until Napoleon sells him.

The pigs, on the other hand, do change.  They are basically just farm animals under Jones.  From the beginning, they take charge.  They teach themselves to read, begin walking on two legs, and begin remaking the tenets of Animalism to give themselves more power and privileges.  They wear clothes, sleep in the house, and drink alcohol.  Soon they are making trades with the men, and eventually you can’t tell the difference.