what hints of future trouble do we get in chapter 2?

After Candy has been caught eavesdropping on Lennie and George the narrative states, "the dog struggled lamely". This foreshadows the dog’s death later on in the book.

There is little light in this book. Sunshine usually comes out in the few instances of hope or commaradere. When Curley's wife shows up in the barn, "the rectangle of sunshine in the doorway was cut off." This represents the shadow her presence will cast in the story.