The boys are all still civilized but are beginning to show signs of the transition to savagery that will gradually occur. Jack would like to kill the piglet, but he has never killed an animal before and really can't bring himself to do it. He is embarrassed about not being able to act the part of the courageous hunter, especially since he appears to be the only boy who owns a knife. He promises that the next time he gets an opportunity to kill one of the many pigs on the island he will show no mercy. His promise is fulfilled. He becomes more and more bloodthirsty and in doing so brings out the innate savagery in many of the other boys who make him their leader. Eventually they graduate from killing animals to killing humans. Ralph himself would have been butchered if the naval officer had not arrived in the nick of time.
The most interesting aspect of Lord of the Flies is the gradual way these well-educated and socialized British schoolboys gradually evolve into savages because of their environment and lack of adult supervision. Jack's first encounter with the piglet, in which he cannot bring himself to kill, dramatizes the tipping point in his metamorphosis.