Beginning in chapter 3 of Animal Farm, we see the pigs starting to grant themselves extra privileges. Although no one appoints them as such, the pigs have taken over the role of supervisors and do not do any of the physical labor that has led to the productive harvest. They seem to have fallen into the role of taskmaster now that the humans are gone.
Even though all decisions on the farm are supposed to be made communally, the pigs have begun quietly making decisions for their own benefit. This includes taking extra milk and apples for their own mash. Squealer defends this unilateral decision to take extra food by claiming that, as the decision-makers on the farm, the pigs need it for all the brainpower involved in their role as supervisors. Really, what we are seeing is the gradual establishment of the pigs as a privileged class. Furthermore, the agenda of Sunday meetings is always dominated by the pigs.
Also, even though the pigs have promised education for all, they seem to be limiting what the other animals actually learn. While they are controlling the flow of information, they go about educating themselves, furthering the divide between themselves and the others.
As this is happening, we see Napoleon set himself apart from all the other animals in particular. He keeps nine dog pups for himself. At this point, the reader can only guess what he is up to, but it seems to foreshadow trouble ahead.