Lots of good points above, for sure the dogs ability (experience, training, genes, etc) has a lot to do with how well they will track down cripples. I can’t take credit for this because I heard it on a podcast, but I now carry a few reflectors and some flagging ribbon with me. If I don’t find the bird in my usual amount of searching, I mark the area where I think the bird went down with the flagging ribbon, go hunt for awhile, then circle back through the area later. That has worked for me a handful of times. I think letting the area clear of old scent and letting the scent of the cripple pool for a bit can help the dog if they’ve lost it. I have also learned that as long as the dog saw the bird fall and was close to it when it went down to just leave the dog alone after that. So many times I’m tempted to call the dog back thinking the clown is off looking for a new bird because he’s no where near where I think the bird went… and sure enough, here he comes with it.