I like that the Duke of Owls always refers to Patou (the dog) by name
Just a small, insignificant detail I guess. But I kind of like how the Duke always refers to Patou by name. The two seem to know each quite well, and despise each other just as much.
I can imagine The Duke being a recurring villain who's showed up on the farm to terrorize the animals many times before the events of what we see in this movie.