The animals point of view is expressed in the last chapter, at least that is how I read the book. The pigs have become indistinguishable from the humans. Separated from their essential animalness, the pigs have become the oppressor and therefore the enemy. They are without empathy and do not identify with the animals at all anymore.
The word despairing comes to mind. Interestingly, only the cynic Benjamin is still around, although even he has grown more depressed. Life is harder for the animals than it has been in recent years, but there is no one around who remembers the past, so with no real "facts" to rely on, they don't really know if their present situation is worse than it was in the past. They see the pigs essentially transformed into the humans they used to think were their oppressors. Right there it must have been clear to them --- their position in the world is where it has always been, at the bottom of the heap. Their own kind are treating them as badly as the humans had (think Republicans/Democrats?). They had believed all kinds of promises that things would get better for them, but it's not going to happen.
Yes. I'll go with despairing.