For brine, in large Dutch oven stir together 1 gallon water, 1/2 cup salt, and 1/4 cup snipped rosemary until salt is dissolved. Rinse inside of chickens. Submerge chickens in brine. Tie 6 of the rosemary sprigs together with 100-percent cotton kitchen string to make a brush. Add rosemary brush to brine mixture. Cover and refrigerate for 6 to 8 hours.

Using a vegetable peeler or zester, remove lemon peel, taking care not to remove any white pith. Cut lemon in half; set aside.

In a small saucepan combine olive oil, 2 garlic cloves, and lemon peel. Cook, uncovered, over low heat just until warm to the touch; remove from heat and set aside.

Preheat oven to 425 degrees F. Remove chickens and rosemary sprigs from brine. Dry chickens with paper towels. Skewer neck skin of chickens to backs. Twist wing tips under backs. In the cavity of each chicken place a lemon half, a sprig of the remaining rosemary, and one garlic clove. Tie legs to tail, if present, or to each other. Cut large potatoes into 1/2-inch slices and halve small potatoes. Place potatoes in a large shallow roasting pan. Sprinkle potatoes with the 1/4 teaspoon salt and the pepper. Using the rosemary sprig brush, baste potatoes with some of the oil mixture. Place chickens, breast sides up, on potatoes in pan. Using the rosemary sprig brush, baste chickens with some of the oil mixture.

Roast, uncovered, 30 minutes. Reduce heat to 375 degrees F. Roast for 45 to 60 minutes more or until drumsticks move easily in sockets, chicken is no longer pink (180 degrees F), and potatoes are tender, brushing twice with remaining oil mixture during first 1 hour of roasting. Remove from oven. Cover; let stand 10 minutes before carving.

Transfer the chickens to a serving dish; surround with potatoes. Sprinkle chickens and potatoes with fresh rosemary leaves and lemon peel strips. Makes 8 servings.