Rinse pheasant breasts and remove skin. (If using chicken, skin if desired.) In a large skillet, heat oil and margarine or butter. Brown pheasant in hot oil mixture until golden. Place in a 2-quart rectangular baking dish or a 2-quart casserole. Sprinkle with salt and pepper. Add mushrooms, onion, and garlic to skillet. Cook until onion is tender. Stir in broth, wine, orange peel, and juniper berries. Pour over pheasant. Cover; bake in a 325 degree F oven for 45 to 60 minutes or until meat is tender.
Using a slotted spoon, transfer meat and vegetables to a serving platter; keep warm.
Pour juices into a saucepan. Discard juniper berries. Stir together sour cream and flour. Add to juices; cook and stir until bubbly. Cook and stir 1 minute more. Pour some sour cream sauce over meat and vegetables; pass remaining sauce when serving. Makes 4 servings.