Blood trailing is something I have trained my dogs to do. first I get the feet and tarsel glands of deer and if you can get a bag or bottle of blood you got a start.
I tie the skinned feet and tarsel glands to a fishing line and pole ,drag it from point to point so I knoe wher the sent is and then get the pup(if you can do it in the morning when the dew is on the grown it helps to hold the sent).get it on the sent and help it follow the trail if it does then at the end let it ply with the skin.
after it trails it a time or two add a little blood in the trail and go from there it take a lot of work.it you can get someone to kill a deer or you kill one , no matter if you see it fall,get the pup and start it where you saw the deer first and let it find that deer.after it finds one or two you have it made. just praise the pup and talk to it all the while it is working. they love praise.