What is significance (the meaning and importance) of the boys' encounter with the wild piglet ?

The novel's first chapter establishes the theme corruption of innocence. Golding emphasizes the childish nature of the boys from the outset of the narrative, and he suggests that many of the struggles that mark their time on the island have less to do with either the natural brutality of the human spirit or the corruption of political society than with the boys' young age and incapacity for responsibility. Jack's impulse to "kill" falls flat when he is confronted with an opportunity to do so, but over the course of the novel his innocence is lost and killing becomes almost second nature.