In chapter four, Mr. Jones assembles men from Foxwood and Pinchfield and plans on attacking Animal Farm. Mr. Jones desires to retake his farm, but the animals have been expecting an attack and have made preparations to defend the farm. Snowball, who allegorically represents Leon Trotsky, studied an old book of Julius Caesar's campaigns, which he found in the farmhouse. Snowball uses the knowledge gleaned from the book to organize and plan an effective defensive strategy to defeat Mr. Jones and his men. During the Battle of the Cowshed, the animals attack the humans in waves and lure their enemies further into the barnyard, where Snowball launches an ambush counterattack. The humans are completely caught off guard when the horses, cows, and pigs charge at them out of nowhere. During the battle, Snowball is wounded, but the animals successfully drive Mr. Jones and his men from the farm.

Snowball studied Napoleon's successful battles to learn some strategy for fending off the farmers who rallied to Jones to help him retake the farm.

He used tactics of both diversion and surprise to win. He even lured the farmers to "chase" the animals to get them into their most vulnerable position before finishing off the counterattack.

The strategy worked, and the farmers were indeed chased away.