The style of Animal Farm is wedded to Orwell’s overall purpose in the novel. As you might have gathered from Orwell’s depiction of the intelligent pigs Napoleon and Snowball, he was skeptical of intellectuals, depicting their sophisticated arguments as masks to cover selfish intentions. To oppose such ‘doublespeak’ (a term Orwell coined in 1984), Orwell sought to express his ideas as simply as he could.
Consider the description as Boxer is taken away from Animal Farm after one of his lungs gives out:
Boxer’s face did not reappear at the window. Too late, someone thought of racing ahead and shutting the five-barred gate; but in another moment the van was through it and rapidly disappearing down the road. Boxer was never seen again. (9.24)
It is perhaps the most heart-wrenching scene in the entire novel, and yet the language is simple and unsentimental. Not a word is wasted in the passage. We do not get descriptions of how the animals’ hearts went out to Boxer or how they panicked when they realized he was about to turn into glue. Instead, we simply learn that they thought of closing the farm gate "too late." We do not get any moralizing on what happened to Boxer or any tearjerker descriptions of how his loss affected the other animals. All we learn is that he "was never seen again." In many ways, the simplicity of Orwell’s writing makes it that much more powerful.