Supertac45, Not all situations allow for "hoof tracking". Frozen ground, many deer on the same trail at the same time, water crossings (deer swim very well) and many other things. Being primarily an archery hunter, I have learned to read about every kind of sign there is and even knowing all this, I still will fall back on my reliable little Jack Russel Terrier (Best game recovery breed on the planet) when all else has failed to leave a sign. Put that little bugger on a 10 foot lead and if that deer is down, he will find it.
Like Zero said, I have shot deer with many different calibres of rifles, many different broad heads, many different shot angles and the one thing that remains constant, you NEVER know how that deer will go down. Barring a CNS hit, they are just as likely to run a mile as they are to drop dead right there. A deer can cover a mile in about 20 or so seconds on a full tilt boggie, flat out, get the hell outta dodge, run. Granted, if left unpushed for a good half hour, they more or less will USUALLY run no more than 100 or so yards before laying down. Thats with a pretty poor hit like a liver shot. Heavily traumatized lung or "spagetti" or heart they will go down fairly quickly but the key is to leave them be for at least 30 minutes. I have seen deer drop in their tracks, look dead as door nails, didn't even look to be breathing, I get down after about 10 minutes, get about 20 yards from it, gets up and covers 200 yards before dropping again. They are an incredible animal to say the least.