Bloodhound tracking blend is designed to help track any animal that is wounded and leaving blood on the trail, bushes, grass, dirt etc. The blood can be several days old and it wouldn't matter as long as the rain hasn't washed it away, you will see a foaming action on contact. Equally important is knowing what isn't blood, if you don't see a foaming action then its not blood. With 4 different color options you can choose a color that's easy for you to see. Each bottle is 28 ounces of blended mix and won't freeze. You can transfer some liquid in to a smaller light weight spray bottle just to have it with you during the hunt or come back to camp for the bottle once you have success.