Personally I believe you did the right thing. A few months ago I was on a hunting trip with some friends in the desert down here in AZ. We were hunting Havolina hog's. Anyway we were driving home and the truck in front of us NAILED a huge jackrabbit. Probably over 18 pounds. We stopped as to not just run it over. It was toasted but was trying to get up so we decided to move it off the road and shoot it to put it out of it's misery. The poor guys whole chest was compressed and crushed so I know we did the right thing.