I have one of the winchester blood tracking lights I got from walmart.
I took a nice spike opening morning of shotgun season The deer never ran out of sight. I field dressed in the back part of my hunting spot and used a ATV to drag it out along my trail. The deer left a good blood trail all the way to my truck.
Wanting to see how this light worked That night I used to to track my way to the truck. I found it does not work as well as they say, It did not work at all on the dried blood or very small spots, on the still wet it did show a little I think it would hale if you know the direction of the deer.