what further examples of the difference between the pigs and the other animals occur

The pigs supervise the others but do not participate in the manual labor.

The pigs set up a study center for themselves in the harness-room, where they study trades using Mr. Jones’s books.

When the wind knocks ripe apples out of the orchard trees, the pigs claim the right to take them all, as well as the bulk of the coming apple harvest. The pigs claim that they need milk and apples in order to power their “brainwork.”