Are you flushing the wounded hens or is your dog finding them? I shot a rooster this year in the edge of a canola field. When i retrieved it , i walked out of the brush exactly how I had walked it. When i got to where the rooster had originally flushed , another jumped up within inches of my feet , brushed against my leg and ran into the brush. I had a shot but My friend was on the other side and I couldn't see him. That bird was determined not to fly , even though his buddy did. I suspect he was injured and couldn't.