why is the scene of the killing of the sow described in such detail?

The boar hunt and the game the boys play afterward provide stark reminders of the power of the human instinct toward savagery. Before this point in the novel, Ralph has been largely baffled about why the other boys were more concerned with hunting, dancing, bullying, and feasting than with building huts, maintaining the signal fire, and trying to be rescued. But when he joins the boar hunt in this chapter, Ralph is unable to avoid the instinctive excitement of the hunt and gets caught up in the other boys’ bloodlust. In this scene, Golding implies that every individual, however strong his or her instinct toward civilization and order, has an undeniable, innate drive toward savagery as well. After the hunt, the boys’ reenactment of the chase provides a further reminder of the inextricable connection between the thrill of the hunt and the desire for power. Robert, the boy who stands in for the boar in the reenactment, is nearly killed as the other boys again get caught up in their excitement and lose sight of the limits of the game in their mad desire to kill. Afterward, when Jack suggests killing a littlun in place of a pig, the group laughs. At this point, probably none of them—except possibly Jack and Roger—would go so far as to actually carry out such a plan. Nonetheless, the fact that the boys find the possibility exciting rather than horrifying is rather unsettling.