In a medium skillet, heat the 2 tablespoons of the butter over medium-low heat. Saute the leeks for 8 to 10 minutes, until softened. Add the apples and cook for 3 minutes more. In a medium bowl combine the leek mixture with the sage, parsley, cornbread and enough broth to moisten. Season with salt and pepper to taste.

Preheat the oven to 400 degrees F. Stuff the birds with the cornbread mixture and tie the legs of each hen together with kitchen twine. Melt the remaining butter. Brush the birds all over with butter and season with salt and pepper. Put the hens on a rack in a large roasting pan, breast-side up. Roast until an instant read thermometer inserted in the thigh registers 170 degrees F., about 80 minutes. Set the birds aside at room temperature, loosely covered with foil, for 10 minutes before carving. Split the hens in half through the breast with a sharp knife or poultry shears, and keep the stuffing intact. Arrange birds skin-side up, on a platter, garnish with sprigs of herbs and serve.