These chapters cover the course of a little over one calendar year. Chapter 5 occurs during what is described as a winter that featured "bitterly hard weather." This is the period in which Snowball developed his plan for the windmill, and was subsequently driven from the farm by Napoleon. The expulsion of Snowball occurs in the late winter, and by the time the ploughing has begun in the spring, Napoleon has adopted Snowball's idea as his own. Chapter Six covers the following summer and fall, and it is in fact an autumn wind storm that blows down the windmill, a disaster that Napoleon is quick to blame on Snowball. Chapter Seven discusses the next winter, another very difficult time that sees an egg-laying strike by the hens, and is followed by the brutal purges conducted by Napoleon in the spring.