Don't use the fox urine you mentioned earlier. Hunters use it to mask their scent. A fox is rarely seen by people because of it's elusive nature, so if a deer smells fox urine, it will assume that this is somewhere the fox frequents. If a fox frequent the area, then the deer will feel comfortable, since foxes prefer secure (little human activity) areas. You do not want the deer to feel comfortable in your grow area!
This is a problem in the best grow areas, where deer are present, because you and the deer are both looking for secure areas with no human activity. I look for deer bedding areas, if they are comfortable enough to take up residence, then I feel comfortable kicking them out and using their beds as plant beds.
If you are a hunter, you can freeze a few bags of guts and put a few pounds of them in the vicinity of your grow every few weeks. Nothing I know of will discourage deer traffic better than a pile of their cousin's guts. If you don't hunt, bag up some fresh road-kill. An added bonus is that most people also avoid the smell of rotting flesh, so it serves to discourage cops, thieves, and hunters. Makes maintenance a little more challenging, depending on which way the wind is blowing!
Fox piss would be good for rabbits, though.