The animals work "like slaves." Heavy irony ensues.
Napoleon starts engaging in trade with the neighboring farms. "Wait a minute," you might say, "I thought there was a rule against trade!" Yeah. That’s what the animals thought, too. Talk to Squealer. They also move into the farmhouse. Talk to Squealer again.
Snowball becomes the scapegoat, which is particularly convenient when the windmill blows down in a gale.