Why is it easy for the pigs to establish dominance over the other animals in Chapter 2 of "Animal Farm"?
The other animals (with the exception of Muriel) are illiterate and well, to put it bluntly, quite stupid. Not only do they have problems learning the alphabet, but they are incredibly naïve. They allow the pigs to take over because they are naturally more intelligent and are, most probably, Old Major's offspring. Their attention is quickly diverted from the essential, even when discrepancies in "equality" arise.
The pigs are also quick to subjugate the other animals under the menace that if they don't do everything they say, "Jones will come back."
The use of intimidation to gain and maintain control crescendoes with the arrival of Napoleon's dogs, then a series of "confessions" and executions in Napoleon's political purge.
The pigs establish dominance b/c they are smarter than the other animals and they develop a solution to the unhappiness the other animals feel, thereby creating a sense of unity and trust. They answer all the questions brought to them and keep the focus on the "bad" humans rather than the fact that they themselves (the pigs) are now ruling over the other animals