In chapter 3, Carlson enters the bunkhouse and begins complaining about Candy's ancient dog. He comments on the awful smell of the old dog and mentions that it can barely eat its food. Candy's old dog is essentially useless and barely living. Although Candy shares a special bond with his old dog, he cannot deny that the ancient dog is close to death. Carlson lacks sympathy and offers to shoot the dog to put it out of its misery. Candy hesitates to allow Carlson to follow through with shooting his dog until Slim gives Carlson the okay. Once Slim agrees with Carlson and tells him to put the dog out of its misery, Candy is helpless and does not stop Carlson from taking his dog outside and shooting it.

The fate of Candy's dog underscores the relationship between the strong and weak on the ranch. The ranch is a hostile, threatening environment, where only the strong survive. Candy's dog is old, useless, and extremely vulnerable. Therefore, Candy's ancient dog cannot defend itself from strong, aggressive individuals like Carlson. This scene not only foreshadows Lennie's tragic death but also underscores Steinbeck's theme regarding the relationship between the strong and weak. On the ranch, strong individuals ruthlessly wield their power by oppressing and harming weaker people. Steinbeck continually depicts how stronger, callous individuals take advantage of weaker characters. For example, Curley immediately challenges Lennie because he knows that he is mentally disabled, and Curley's wife threatens Crooks because he is a powerless black man. Similarly, Candy's dog is weak and vulnerable, which is why Carlson ruthlessly kills it.