Tough subject. First of all, when a dog is on a running bird, you want the dog to stay on the bird, not in range. It is up to you to keep up with a dog in persuit. To get the dog working more closely is a question I cannot help with. I traing my Lab at the English Springer Spaniel club I joined for training purposes. I help these guys train their dogs and in trade, they help me. This may be a step you could look at as well. If you want a pheasant dog, train with the pheasant hunters.
You might find a club near you here. Good luck.
http://www.essft.com/
Good Luck with the Duck!