Are you sure that it was a clean miss? Like Spurhunter mentioned, he may have taken some pellets.
If you have opportunity, I'd go back and walk the path that he went. I hit a bird one year that was able to take flight, but not very high. I knew he was hit. My heart sank as he flew out of sight. However, I walked that way just in case he might have hunkered down once landing. I was at the edge of a field, and when I came to a pretty thick patch of briers, I walked around it checking. I just saw the tip of a tail feather. He was dead and had dived into that brier bush.
As far as the others, it sounds like they are ready to die and are probably back there now.