Piggy serves as the symbol of rationality and logic in Lord of the Flies, and it is partially because of his role as this symbol that the bullying against him seems especially pronounced. Though it is obvious to most readers in our current time, when bullying education and prohibition is a cornerstone of many school systems, this was not necessarily the case in the 1950s, when Lord of the Flies was published. It's important to note when reading that, in the 1950s, not only might the treatment of Piggy have been normal and accepted by adults had they been on the island, it's likely that the adults in Piggy's life had treated him the same way Jack and the other boys that "bullied" him do.
Piggy is immediately set apart from the others through physical description. Until they exchange names, Ralph is described as the "fair boy" and Piggy as the "fat boy." Piggy asks Ralph his name, but Ralph does not reciprocate the inquiry. Within just a few sentences, readers learn that Piggy is afflicted with asthma and also wears glasses. These characteristics of his serve to lay a foundation of the potential for bullying--but Piggy is also quite likable. He's agreeable, and he's incredibly optimistic.
The incidents of bullying happen most when Jack Merridew is around, starting from the moment all of the boys come together.
Piggy asked no names. He was intimidated by this uniformed superiority and the offhand authority in Merridew’s voice. He shrank to the other side of Ralph and busied himself with his glasses.
Piggy's intelligence and ability to read other people protects him from an immediate attack from Jack; he knows to stay out of Jack's way.
Later, though, that is impossible. Piggy begins to gather names, but Jack doesn't want to be called "Jack"; he wants to be called "Merridew."
“Kids’ names,” said Merridew. “Why should I be Jack? I’m Merridew.” Ralph turned to him quickly. This was the voice of one who knew his own mind.
“Then,” went on Piggy, “that boy—I forget—”
“You’re talking too much,” said Jack Merridew. “Shut up, Fatty.”
Jack's attacks on Piggy continue, and turn from verbal to physical when Jack physically takes Piggy's glasses off his face against Piggy's will.
Jack pointed suddenly. “His specs–use them as burning glasses!” Piggy was surrounded before he could back away. “Here–let me go!” His voice rose to a shriek of terror as Jack snatched the glasses off his face.
He physically attacks Piggy again after the boys let the fire go out. This attack is more violent than the first.
This from Piggy, and the wails of agreement from some of the hunters, drove Jack to violence. The bolting look came into his blue eyes. He took a step, and able at last to hit someone, stuck his fist into Piggy’s stomach. Piggy sat down with a grunt. Jack stood over him. His voice was vicious with humiliation.
“You would, would you? Fatty!”
Ralph made a step forward and Jack smacked Piggy’s head. Piggy’s glasses flew off and tinkled on the rocks.
The book then balances for several chapters, as Piggy survives the way many bullying victims do--by blending in and by being helpful when it won't draw a tremendous amount of attention.
Piggy could almost consider himself accepted, even after Jack and the other hunters steal his glasses (for the theft was not an act of bullying; the hunters would have stolen the glasses from anyone who had them), until Roger's assault on Piggy, which is a final act of bullying that proves fatal. Whether Roger knew that pushing the boulder would actually kill Piggy or just scare him is unknown; either way, it was an attack on him that happened out of a desire to control and intimidate.
When considering what examples of bullying exist in the novel, it's important to consider the context of bullying from the 1950s as compared to and contrasted with the 2010s. Though there are a number of differences, some examples are clear, time-tested tactics of bullies and, for that reason, serve as evidence that Piggy was bullied by at least Jack, and by other boys as well.