What is the significance of boys' encounter with the wild piglet?

The boys are shocked when they first encounter the piglet. Jack moves to stab it with his knife but cannot. All the boys understand the enormity of taking away life. The piglet reflects the boys' first foray into the taking of another life,

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.