One of Candy’s short-term goals is to keep his dog. The other men want him to get rid of it.
Candy’s dog is very old, and smells. It cannot eat anything except milk. Candy does not notice the smell, but the other men complain about it.
"God awmighty, that dog stinks. Get him outa here, Candy! I don't know nothing that stinks as bad as an old dog. You gotta get him out." (ch 3)
Candy has had the dog ever since it was a puppy. He is very fond of the dog, even though he knows that it is old and hard to take care of. The dog no long has any real use around the ranch. The men also point out that the dog only suffers. The men tell him he can just get one of the puppies that have just been born, but it’s not the same to Candy. He loves his dog.
Candy’s efforts to keep his dog safe are unsuccessful. Ultimately, he has to let them shoot the dog.
A shot sounded in the distance. The men looked quickly at the old man. Every head turned toward him.
For a moment he continued to stare at the ceiling. Then he rolled slowly over and faced the wall and lay silent. (ch 3)
Candy considers his dog a metaphor. Candy himself believes that when he is no longer useful they will get rid of him, just as he has to get rid of the dog. Candy’s shooting of the dog also foreshadows George’s needing to shoot Lennie at the end of the story, when he accidentally kills Curley’s wife.