Jack and the others go pig hunting a lot, so I do not know if you are referring to one particular hunt or not.
In general, the hunts are not exactly evil, especially at first. The hunters are more irresponsible and less evil at first.
But then things get worse. For one thing, you have the boys start to do more and more violent things after they get back from hunting. Second, when the boys manage to kill a pig for the second time, they brutalize the pig in ways that are really unnecessary. At that point, they are no longer hunting for food or even for adventure. Instead, they are trying to hurt things and you could say that is evil.