Why doesn't Jack kill the pig in Chapter 1 of Lord of the Flies?

In Chapter One of William Golding’s The Lord of the Flies, the reader is introduced to the characters, the young boys stranded on a deserted island, and the first glimmers of divisions and conflicts to come are exposed.  Among those conflicts is the one between Ralph and Jack, the latter accustomed to being the leader among the boys in the choir and prone to displays of anger and meanness.  Early in the story, the boys have assembled for what will be their first meeting, and Jack’s wastes no time revealing the nature of his character.  Addressing Piggy, a sensitive, overweight boy with glasses, Jack interrupts saying, “You’re talking too much . . . Shut up, Fatty.”  And, when the boys decide to elect a leader, it is Jack who immediately announces his intentions: “I ought to be chief,” said Jack with simple arrogance, “because I’m chapter chorister and head boy. I can sing C sharp.”

For all of Jack’s obvious character flaws, however, Golding reminds us that these are children, and that the challenges that confront them will expose the weaknesses that boys like Jack try desperately to conceal.  Having stumbled upon a piglet “caught in a curtain of creepers,” the boys approach it as a the potential source of food it is.  Jack’s reluctance to engage in the barbaric act of killing the small animal with his knife, however, is described as follows:

“The three boys rushed forward and Jack drew his knife again with a flourish. He raised his arm in the air. There came a pause, a hiatus, the pig continued to scream and the creepers to jerk, and the blade continued to flash at the end of a bony arm. The pause was only long enough for them to understand what an enormity the downward stroke would be. Then the piglet tore loose from the creepers and scurried into the undergrowth. They were left looking at each other and the place of terror. Jack’s face was white under the freckles.”

He can’t admit it, of course, but Jack is afraid of the actual act of killing a living being, even an animal that can provide sustenance.  The thought of the bloody mess associated with stabbing and slaughtering the piglet is more than he can bare.