To roast the garlic, preheat oven to 425 degrees. Break the garlic into individual unpeeled cloves, season with salt and pepper and 1 teaspoon of olive oil. Place the garlic in a heat-proof baking dish and place in the oven. Bake 25 minutes and set aside. Put chickens in a large bowl and add olive oil, corn oil, split head of garlic, rosemary and half the thyme sprigs. Cover and refrigerate. Let stand turning occasionally, for 24 hours. When ready to cook, scrape the herbs from the chickens, season with salt and pepper. It is not necessary to truss them. Preheat the oven to 450 degrees. Heat a heavy skillet large enough to hold the chickens in one layer without crowding, or use 2 skillets. Place the chickens in the skillet(s) breast side down. Cook until the breasts are nicely browned, about 4 to 5 minutes. Turn the chickens to the opposite side and then on their backs. Brown each part of the chickens as they are turned. Place the chickens in the oven and bake for 30 minutes. Remove the chickens from the skillet and pour off the fat. Add the wine and vinegar (if 2 skillets are used, use half the remaining ingredients for each skillet), the broth, the roasted garlic cloves, the remaining thyme sprigs tied in a bundle and salt and pepper to taste. Bring to a boil and cook for about 2 minutes. Swirl in the butter, stirring, and add any liquid that may flow from the inside of each chicken. Carve the chickens and arrange on dinner plates. Garnish each serving with thyme sprigs and roasted garlic cloves. Spoon the sauce over and serve Note: For a wood smoke flavor to the roast chicken - place a roasting pan on top of your stove burner. Add 1 cup of apple wood chips and cover with a wire rack. This must be done in a well ventilated area, or you can heat the pan on the stove and then bring it outside. Heat the pan on the burner on high heat until the wood chips begin to smoke. Place the chickens into the rack and cover with another pan (inverted) or aluminum foil. Smoke for about 5 minutes then remove from pan and begin browning. An old roasting pan should be used for this technique