What Symbolizes the theme "Loss of Innocence" in LOTF?

I think the killing of the sow represented a total loss of innocence. This is a shocking scene. I still don't like reading it. Golding uses rape imagery to describe the kill. If you examine it again, you will see. The boys are not content to simply kill the sow. They abuse it with brutal sexual undertones before the savagely slaughter it.