my very limited knowledge is from helping to train a drahthaar. the dog is not tracking it is blood trailing. the standards test is about 1 cup blood on a 600 meter(its german) trail with 2 90 degree turns, left for appx 11 hours. the dog will run down this as fast as you can keep up. Rain doesnt effect this as much as you may think. Sounds like bs, and if i hadnt seen it i would have doubted it too.
