The pacing of this passage affects the reader's interpretation of the text by conveying the characters resolve to finish the windmill.
By reading the excerpt, the reader understands that the animals are not worried about not having too much stores of food because they are willing to compensate this need with the build of the windmill.
The excerpt shows that they are calm because they know how to solve the lack of food, and this calmness is transmitted particularly by this sentence: "the stores of food were none too plentiful, but the windmill compensated for everything. It was almost half built now".