How does the author show the increase in evil the boys lord of the flies?

There is an awful lot of savagery throughout Lord of the Flies. At the beginning, they are too scared to even kill a pig, " because of the unearable blood" with Jack being unable to stab it. This however only makes makes him more urgent to prove himself by being savage. They also decide to have rules, but Jacks savage side is showed with his urgency to unish rule breakers. We are then directly told that Jack has a savage side "the compulsion to track down and kill that was swallowing him up", but at this moment we are safe, because he only wants to kill pigs. Meanwhile, the other boys are still abiding by the rules of the outside world, like when roger is throwing rocks at Henry, "there was a space around Henry... into which he dare not throw" After this he killing begins- with them first killing a sow (mother female pig). They have killed the piglets mother, and the piglets too, showing they have no regard for the innocnece. They are also loosinh all sense, as they kill babies, so the pig supple will soon run out. They get more and more savage, with thm becaoming a tribe and killing simon, with a war ance and fire.