Jack hesitates to kill the pig because of the enormity associated with taking the life of a creature and the massive amount of blood involved in the ordeal. At this point in the story, Jack and the other boys are still conditioned to obey the rules of society and behave civilly. None of them have killed an animal before, so the violence and blood involved in taking the helpless creature's life are too much for Jack to endure. Although Jack wishes to be viewed as a strong, fearless hunter, he cannot force himself to bring the knife down to kill the pig.

Instead of taking advantage of the rare opportunity, Jack hesitates and holds his knife in the air while the pig escapes the creepers. Once the pig escapes, Jack makes an excuse by saying that he was searching for the right place to stab. Following the incident, Jack states that the proper way to kill a pig is to cut its throat and promises to kill the next one he sees.

Later on, Jack and his hunters become acclimated to the island and gradually transform into bloodthirsty savages. Once Jack and the choir boys kill their first pig, they focus all their attention on hunting and begin neglecting their agreed-upon duties. Eventually, Jack's obsession with blood and violence reaches a crescendo when he hunts Ralph throughout the island.

A squealing piglet trapped in the undergrowth gives Jack a golden opportunity to show off in front of the other boys. It would be the easiest thing in the world for him to step forward and kill the creature with one mighty blow. Jack would then have established himself as something of a hunter, a very important role on the island.

And yet, when it comes to the crunch, Jack can't quite bring himself to do it. He lifts the knife in the air, seemingly ready to strike. But he hesitates, which allows the piglet to untangle itself from the jungle creepers and run off.

Not wanting to appear weak and feeble in front of the other boys, Jack claims that he was simply choosing the right place to strike. But that's a pretty lame excuse. In actual fact, Jack is too civilized at this stage of the story to shed the blood of another living creature. He is struck by the sheer enormity of what is involved in sticking the knife into a pig and seeing the blood come spurting out.

Given what will happen later on in the story, this is somewhat ironic, to say the least. In due course, Jack will lose whatever moral qualms he may have had about spilling blood, whether it's the blood of animals or humans.

On their way back from exploring the island, the boys hear a squealing piglet, which is stuck in the creepers. As Jack approaches the piglet, he raises his knife in the air but hesitates to bring it down. Jack's brief hesitation allows the piglet to escape from the creepers. Immediately after the piglet escapes, Jack insists that he was choosing the right place to bring his knife down, which is why he hesitated to kill the defenseless animal. However, Golding exposes the true reason for Jack's pause by writing,

"They knew very well why he hadn't: because of the enormity of the knife descending and cutting into living flesh; because of the unbearable blood" (22).

Essentially, the boys have been on the island a short time and still have remnants of civility. None of the boys are used to killing animals. As the novel progresses, Jack and the majority of the boys abandon their civil personalities as they descend into savagery.

Jack paused because of the enormity of taking a life, but he said he was choosing a place to stab.

The boys have a desperate need for meat, and Jack’s choir is chosen to be hunters.  However, the hunting is not just for food.  It is a show of dominance and power.  Simon, Ralph, and Jack find a piglet, and Jack draws the knife “with a flourish” but does not immediately kill the pig.  Instead there is a pause.

The pause was only long enough for them to understand what an enormity the downward stroke would be. Then the piglet tore loose ….They were left looking at each other and the place of terror. Jack’s face was white under the freckles. (ch 1)

Jack says he was looking for a place to stab the piglet, and the boys argue about how to kill a pig.  Ralph tells him to “stick” it, and Jack says you are supposed to cut the pig’s throat and let the blood run out.  The other boys know that stabbing the pig would result in “unbearable blood.”

Jack’s embarrassment at not killing the pig demonstrates that he is still young and immature.  He is not completely bloodthirsty yet.  He isn’t lost.  The thought of killing the pig and draining his blood was, at this point, too much for him.  However, the shame of not doing it was worse.  Soon Jack embraces his barbaric side, blood and all.

In Lord of the Flies, why does Jack hesitate at his first opportunity to kill a pig?

Jack hesitates the first time he has a chance to kill a pig because civilized norms still guide his behavior, including prohibiting him from killing. He is the same as the other boys, all of whom, despite being hungry and having need of the piglet for food, hesitate at the idea of taking a life. They all feel shame, too, at letting the piglet escape.

Jack, however, determines that this will not happen again:

Next time there would be no mercy

Yet Jack has work to do before he can become the fearless leader who can kill without a second thought. He has to find a way to shed his conscience and his sense of shame. He finds that in painting his face with a mask:

He capered toward Bill, and the mask was a thing on its own, behind which Jack hid, liberated from shame and self-consciousness.

Jack can act bravely as long as he has adopted a different persona, one who is not the choir boy held in place by his superego and civilization. Painted, he can become a new person, one guided by his id or most basic, uninhibited emotions.

Golding shows that Jack's behavior is formed by environment, not innate or inborn. Jack undergoes a process in which he embraces his atavism gradually. He is looking for a way to gain power and knows he can't get it by trying to out-Ralph Ralph. He realizes that his route to power comes from stepping out of the normal routines and offering the boys something more alluring than Ralph's normalcy: the opportunity to indulge their fantasies. He benefits from being in a place that offers the opportunity to step out of the "self" that society has imposed on him.

In Lord of the Flies, why does Jack hesitate at his first opportunity to kill a pig?

Ralph, Jack, and Simon are walking in the forest at the end of chapter 1 when they spot a piglet who has become entrapped in creepers, or vines. The pig is terror-stricken as the boys approach and tries desperately to free itself.

Jack draws his knife "with a flourish." This piglet would provide much-needed nourishment for the boys beyond the fruits and plants they can harvest. Jack holds the knife high in the air and is poised to end the piglet's life, which would position him as a strong leader among the other boys.

Yet in that moment, Jack hesitates. This is a reminder that Jack isn't entirely evil. In this moment of hesitation, Jack stands poised between a world of order and a world of savagery. At this critical point, Jack hasn't quite morphed into the brutal boy who will become a murderer. He understands that taking a life, even the life of a pig, is a weighty decision. Jack comprehends the sacred nature of life and understands what an "enormity the downward stroke would be." Jack's face turns white as he struggles with that decision, and the pig gets away.

Jack is angry with himself after the pig escapes and vows that next time, he will show no mercy. While Jack holds on to the remnants of a structured and orderly society in chapter 1, those feelings are quickly replaced with a boy who is determined to spill the blood of any animal or boy who crosses him.

In Lord of the Flies, why does Jack hesitate at his first opportunity to kill a pig?

At the end of chapter one, when Jack, Ralph, and Simon are exploring the island on which the boys have just crash landed, Jack encounters a piglet caught in some vines.  With bravado, Jack whips out his knife.  He had his arm poised above the piglet as if ready to kill it.  He hesitates for a moment and the pig gets away from him.  What caused his hesitation was that he still has the rules of civilization in him.  These rules keep the "beast" that Golding felt every person carried within him, at bay.  Jack is too civilized yet to kill a living creature - up close and personal.  He sees this as a weakness in him and he is embarrassed by his hesitation and says it was because he was looking for a place to stick the piglet.  He vows that next time, the pig won't get away.  This vow opens the door to the savagery that will overtake him and many of the boys.  This inner savage is the beast that the boys have to fear on the island.

In Lord of the Flies, why does Jack hesitate at his first opportunity to kill a pig?

This is the bit from the novel you need, from the end of the first chapter:

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....

“Why didn’t you—?”

They knew very well why he hadn’t: because of the enormity of the knife descending and cutting into living flesh; because of the unbearable blood.

“I was going to,” said Jack.

Jack pauses because he's just a boy, he's never killed anything before, and the actual act of cutting into a live creature with a knife was just too much for him. The blood which followed would be "unbearable". So Jack hesitates, and the pig escapes.

It's a clear sign from Golding that Jack doesn't start off as a monster. He can't kill a pig, never mind Pig-gy. But, as the novel continues, Jack's trajectory moves steadily toward murder and brutality.

Why is Jack unable to kill the pig in Lord of the Flies by William Golding?

Perhaps, it is less a question of Jack's being from a civilized society and more his socio-economic class that prevents his killing the pig. For, there are many civilized people who slaughter livestock such as pigs, cattle, and chickens. Farmers. ranchers, shepherds, etc. and their sons have killed animals, sometimes out of mercy and sometimes for food as have hunters who shoot wild boar, elk, deer, etc. But, judging from the choir uniforms and the group of all boys, Jack and the others have most likely attended a rather exclusive school and are probably residents of higher-level neighborhoods in urban areas. And, in all fairness to Jack, shooting an animal, or even killing one penned or tied is, indeed, different from impaling one with a spear as it charges by as there is also the element of surprise in this venture. However, as already mentioned, as Jack sheds his black cape and reverts to a creature closer to the earth himself and experiences hunger for meat, his qualms about non-essentials disappear.

Why is Jack unable to kill the pig in Lord of the Flies by William Golding?

Lord of the Flies by William Golding is set on a tropical, deserted island, and the characters are all English school boys. The reason that is particularly significant is that English school boys certainly know right from wrong and how to be obedient to rules; however, if one were going to break the rules, a deserted island might be the place to do it.

One of the "rules" of society is that people should not kill. Of course this is true about human beings, but it is equally true about animals. People in a civilized society just do no go around killing things, even a school boy who carries a big knife around with him.

Jack is not a pleasant boy. In fact, he is not even a very nice boy. He talks big, bragging about what he is going to do if he ever gets a chance to kill a pig for meat. We take that for what it is, bragging, even though we do see him slashing candlebud bushes with his knife just because he has no use for them. It is true that, if we believe any of the boys will really use a knife to kill, it would be Jack; however, we know something he does not appear to know--killing something is a very serious matter. 

When he is exploring the mountain with Simon and Ralph, Jack sure does a lot of talking about killing a pig, and he finally gets his big chance to do it. Of course he does not do the deed. After he fails to act, he makes stutters around and makes excuses. and things are a little uncomfortable between the three of them for a bit. While Jack does not ever actually admit exactly why he did not stab the pig, the other two boys know.

They knew very well why he hadn’t: because of the enormity of the knife descending and cutting into living flesh; because of the unbearable blood.

Jack knows it, too. These are civilized boys, not savages, and stabbing a living thing with a knife is just not part of their lives. The thought of the consequences--terrible death and blood--is just too much and that is what keeps Jack from acting.

Of course, after that Jack does violently stab a tree with his knife, but he does so more out of anger, embarrassment, and bravado than out of any real change of heart. It is not the same, and they all know it. Jack determines that "next time there would be no mercy." This is an ominous foreshadowing of things to come. 

So, Jack is not able to kill the pig because killing is not something well bred and civilized people do, even young, impetuous boys. Jack is not hungry enough, desperate enough, or bloodthirsty enough to do it in the first chapter of the novel. 

For more analysis on Lord of the Flies, please take a look at the excellent eNotes site linked below. 

In Lord of the Flies, why do the boys refuse to kill the pig at the start of the chapter?

At the beginning of the novel, the boys are exploring the island, and they come across a piglet that is caught in between vines and roots. As the piglet is trying to escape, the three boys get closer, and Jack draws his knife. However, Jack hesitates and thinks about what he is about to do. His hesitation allows the piglet to run free from the creepers, and Jack makes several excuses as to why he did not kill the piglet. He tells Ralph that he was looking for the right spot to stab the pig, but the reality is that he never killed anything before and was afraid of the massive amounts of blood. The reason Jack did not kill the pig reveals that the boys are still under the influence of the civilized world. As the novel progresses, Golding portrays their descent into savagery. Initially, the boys are civilized and think twice before engaging in violent acts, but as the novel progresses, they begin to follow their primitive instincts.