Blood Trailing - Let your dog pick its reward
When training a dog for blood trailing/tracking let your dog choose its reward for best results.
in a nutshell the handler has two choices, a food reward or a toy/tug reward. Both have advantages and disadvantages, the key to K9 performance is rewarding the animal with the reward it wants, not what serves you best.
This will take some observation on the part of the handler before training starts, when the animal is hungry present some food and a toy - determine which it gravitates towards.
Now the dog has told you which it prefers as a reward its time to narrow the selection down to one type of food treat or one type of toy/tug. For a food reward it will not be the dogs regular food as it will only be used during training. For a food reward present a variety of treats to determine which it likes, something smelly like smoked meats or cheese may be a good start. For a toy/tug reward try a ball, a squeak toy, or a tug with a canvas cover. Regardless of whether your dog will be getting a food treat or a toy/tug this item will ONLY be used for training. The purpose of this is to build the most important element of any trailing dog - DRIVE. The reward will be given immediately (within 30 seconds) after a successful part of the training has been accomplished, no success no reward.
Regardless of whether your dog is a food reward or toy reward training should be done on an empty stomach, hungry dogs simply work better and you will avoid the dreaded stomach flip when a dogs intestines twist around a full stomach.
Remember to experiment, I once worked with a dog that went nuts over empty water bottles that made a crinkly noise.
Pro tip - for a food reward dog keep some deer meat from last year and try it - dogs love deer meat. For a toy reward dog try dipping a tennis ball in deer blood and throwing it into the bush, your dog will have a great time looking for it and it will also strengthen its motivation.