What are some examples of foreshadowing in Of Mice and Men by John Steinbeck?

In his novella Of Mice and Men John Steinbeck foreshadows the key events which dominate the end of the novel. Foreshadowing is the use of clues that suggest events that have yet to occur. There are three distinct episodes of foreshadowing in the book.

First, the reader learns in chapter one that Lennie is often deadly to small animals. He is obsessed with soft things that he can pet, but he doesn't realize his own...

In his novella Of Mice and Men John Steinbeck foreshadows the key events which dominate the end of the novel. Foreshadowing is the use of clues that suggest events that have yet to occur. There are three distinct episodes of foreshadowing in the book.

First, the reader learns in chapter one that Lennie is often deadly to small animals. He is obsessed with soft things that he can pet, but he doesn't realize his own strength. We learn that his Aunt Clara would give Lennie mice but they always ended up dead. Lennie explains,

“They was so little,” he said, apologetically. “I’d pet ‘em, and pretty soon they bit my fingers and I pinched their heads a little and then they was dead—because they was so little."

His handling of mice foreshadows the death of the puppy in chapter five. Lennie is in the barn mourning his puppy when Curley's wife comes in.

The episode with Curley's wife in chapter five is foreshadowed in chapter one and again in chapter three. While the two men were working in Weed, Lennie saw a girl in a red dress and wanted to feel the dress. When she screams, he holds on and is eventually accused of rape. George explains to Slim in chapter three:

“Well, he seen this girl in a red dress. Dumb bastard like he is, he wants to touch ever’thing he likes. Just wants to feel it. So he reaches out to feel this red dress an’ the girl lets out a squawk, and that gets Lennie all mixed up, and he holds on ‘cause that’s the only thing he can think to do. Well, this girl squawks and squawks. I was jus’ a little bit off, and I heard all the yellin’, so I comes running, an’ by that time Lennie’s so scared all he can think to do is jus’ hold on."

The scene with Curley's wife is virtually the same. While Lennie is stroking Curley's wife's hair when she attempts to pull away and Lennie holds on. When she screams, he gets scared and then angry. Steinbeck writes:

And she continued to struggle, and her eyes were wild with terror. He shook her then, and he was angry with her. “Don’t you go yellin’,” he said, and he shook her; and her body flopped like a fish. And then she was still, for Lennie had broken her neck. 

The third episode of foreshadowing is when Carlson kills Candy's dog. Carlson claims the dog is suffering and should be put down. He suggests that Candy do it, but the old man doesn't have the heart to kill the dog he raised from a puppy. He later regrets the decision and tells George,

“I ought to of shot that dog myself, George. I shouldn’t ought to of let no stranger shoot my dog.”

George remembers these words and when Curley's wife is found dead he makes the fateful decision to kill Lennie himself rather than let Curley or the other men get to him first. George has told Lennie to return to the spot by the Salinas River which is the setting of chapter one if any trouble occurs, and that's where he's found in the final scene. Like the dog, Lennie needs to be put down so George shoots him in the back of the head with Carlson's Luger, the same gun used on the dog in chapter three.