The animals work sixty-hour weeks on the windmill, Napoleon begins trading with humans, the pigs move into the farmhouse, and the windmill collapses in a storm.
During this year the animals work harder than they have worked before. In addition to all regular farm labour, they are required to contribute several hours a week to the windmill. Napoleon announces there will be voluntary Sunday afternoon work, but animals who do not participate will have their rations halved. The animals work sixty hours a week. They are compensated with the knowledge that they are working for themselves.
The windmill proves very difficult. Moving the stone down from the quarry requires the animals to drag it up the hill and tip it over the edge to break it into manageable pieces. Without any mechanical means of doing this, it is Boxer who makes the decisive contribution, dragging loads heavier than any other animal can manage, rising before dawn and working until dark.
By the autumn there is a problem: the farm needs iron, nails, string, paraffin, and dog biscuits, none of which can be produced on the farm itself. Napoleon announces that the farm will enter into trade with the neighbouring human farms. He appoints a solicitor named Mr. Whymper to act as his agent. Mr. Whymper visits once a week. This is contrary to one of the resolutions passed after the Rebellion: no animal was to have dealings with humans. Squealer explains that this resolution never existed. It was not written anywhere. Perhaps the animals imagined it.
The pigs move into the farmhouse. They sleep in the beds. Some animals dimly remember that one of the commandments said something about beds. Clover asks Muriel to read the relevant commandment. Muriel reads: "No animal shall sleep in a bed with sheets." The commandment apparently always included the qualifier. The animals had simply forgotten. Squealer explains that a bed is merely a place to sleep, and that removing the sheets from a mattress makes it perfectly consistent with the commandment. The pigs need comfortable accommodation to do their thinking work properly. And surely the animals do not want Mr. Jones to return?
In November, an unusually violent storm sweeps over the farm. In the morning, the animals find the windmill in ruins: the walls have collapsed. Napoleon addresses the animals and announces without hesitation that Snowball has done this. Snowball has sneaked onto the farm in the night and destroyed the windmill out of spite and revenge. The evidence is Snowball's footprints, visible all around. Napoleon sentences Snowball to death. The animals are shocked, but Napoleon's certainty silences their doubts. He calls on the animals to begin rebuilding immediately. "Forward, comrades!" he says. "Long live Animal Farm! Long live the windmill!"
The chapter is the novel's first extended demonstration of normalisation: the process by which each new violation of the original principles is made to seem unremarkable. Trade with humans is one of the things the animals agreed never to do; now it is happening, and there is no written record of the agreement. The pigs are sleeping in beds with sheets, and then without sheets, and then the commandment has always said without sheets. Each step is small enough to accept; the accumulation is total.
Mr. Whymper is an interesting figure: a human agent employed by the pigs to conduct their business with the human world. He is not a villain; he is a solicitor making money. His existence shows that Animal Farm is already becoming integrated into the human commercial system it claimed to replace. Napoleon is not conducting trade with humans on principle; he is doing it because he has no choice. But his doing it is the thing that was never supposed to happen.
The windmill's collapse has a straightforward meteorological explanation: a November storm with violent winds. Napoleon's instant attribution of the collapse to Snowball is one of the novel's clearest demonstrations of scapegoating. There is no investigation, no evidence other than footprints, no possibility of questioning the account. The animals accept it because the alternative, that the windmill fell due to Snowball's initial warning that the walls were too thin, would suggest that Napoleon's insistence on thinner walls was responsible -- an implication that cannot be permitted.
The rally at the end of the chapter, Napoleon's call to rebuild with its revolutionary slogans, is a masterclass in manufactured enthusiasm. The animals have just suffered a significant setback; they are being asked to interpret it as an occasion for renewed commitment. And they do, because Napoleon has arranged the situation so that the only available response is forward.