I would imagine the leak will be somewhere close to the rad, if you hit the deer head on!!  It will probably only leak when the engine is hot, and the water is under pressure.  I'd run the car up hot then start looking around the front end for leaks.  Is there visible damage on the rad?  It may be punctured, and  the water running down the finns, where you wont see it very well
                 Rob
                
 September 2006