How to Make It
In a medium saucepan, bring 8 cups of water to a boil. Stir in the rice and 1 teaspoon salt and cook over moderately high heat, stirring occasionally, until tender but still slightly firm, about 25 minutes. Drain the rice and transfer to a large bowl.
Preheat the oven to 350°. Spread the nuts on a baking sheet and toast for about 7 minutes, or until lightly browned and fragrant. Transfer to a large plate to cool. If using hazelnuts, rub them vigorously in a kitchen towel to remove the skins. Coarsely chop large nuts, such as hazelnuts and walnuts. Add the toasted nuts to the rice along with the raisins, 1 1/2 cups of the chicken stock, the parsley, thyme and rosemary. Season with salt and pepper.
Preheat the oven to 475°. Stuff each hen with 1 cup of the rice and tie the legs together with cotton kitchen string; wrap the remaining rice in foil and set aside. Set the hens on racks in 2 large roasting pans, brush them with the melted butter and season with salt and pepper. Roast in the upper and lower thirds of the oven for 10 minutes. Switch the pans, baste the hens with 1/2 cup of the stock and roast for 10 minutes longer.
Reduce the oven temperature to 350°, baste the hens with another 1/2 cup of the stock and roast for about 25 minutes, until the birds are pale brown; baste occasionally. Raise the oven temperature to 400°. Switch the pans and baste the hens with the remaining 1 cup stock. Roast for about 30 more minutes, basting a few times, until the hens are richly browned and the temperature of the inner thighs registers 180° on an instant-read thermometer. Add water to the pans if the liquid evaporates during cooking. During the last 25 minutes of cooking, add the reserved stuffing to the oven and cook until heated through.
Transfer the hens to a large platter and cover loosely with foil. Spoon the reserved stuffing into a bowl and keep warm. Set each roasting pan over 2 burners over moderately high heat and add 1 cup of water to each. Boil the liquid, scraping up the browned bits, until flavorful, about 4 minutes. Strain the pan juices into a narrow measuring cup or bowl and skim the fat from the surface. Season with salt and pepper.
Pour the pan juices into a gravy boat. Cut the strings from the hens and serve, passing the pan juices and extra stuffing at the table.