The line is: "We thought it was better to go under the high wire fence at the rear of the Radley lot, we stood less chance of being seen. The fence enclosed a large garden and a narrow wooden outhouse."
In literature, "foreshadowing" signifies that the narrator is giving the reader a hint as to what will happen later on in the story. This line foreshadows that Jem will later have trouble with the high wire fence when trying to escape from Radley's backyard.
