I put a deposit on a Redline Airedale pup a month ago, with the idea of training it for this purpose.
In Az, we can use dogs, on a leash "until it is determined the animal is still alive", at which point the dog must be taken off the trail.

It is quite common to see people on FB post looking for blood trailing dogs. Figure it might be a decent way to make a little side cash, and get more time in the woods.