Good Lord. You must not have many scavengers around. I shot a decent size sow and a couple of piglets a couple of weeks ago and when I went back to fill the feeder about 5 days later I had to search for remains. I found one section of spine about a foot long and searched for the head and never could find it.
Shoot at my place you can leave a boar in the middle of a 10 acre field and buzzards wont even touch it. They just kind of melt away over a several month period.