Position a rack in the center of the oven and heat the oven to 400 degrees.
In a medium sauce pan, combine the orange juice and pomegranate juice. Bring to a boil and cook over medium heat, uncovered, until the juice is reduced to 3/4 cup – about 15 minutes. Stir in fresh thyme, ground cinnamon, 1/2 tsp. salt and 1/2 tsp. black pepper.
Divide the juice mixture into two small bowls. Add chicken stock to one and set aside. In the other bowl, add 1 Tbsp. of the canola oil.
In a large glass, ceramic, or metal baking dish (10 x 15 x 2) scatter the sweet potatoes, parsnips, and onion. Toss them with 2 Tbsp. canola oil and season with salt and pepper.
Arrange the chicken, skin side up, on top of the vegetables. Brush the chicken with the juice-oil mixture (use it all up). Place the pan in the oven and roast for 30 minutes.
Remove the pan from the oven and reduce the temperature to 375 degrees. Pour the juice-broth mixture around the chicken and over the vegetables. Return the dish to the oven and continue to cook until vegetables are tender and chicken pieces are cooked (check with a thermometer – pieces should be 165 degrees) – approximately 30 minutes.
Serve chicken and vegetables with the pan juices on a platter or individual plates and garnish with fresh pomegranate seeds, orange zest, and fresh thyme if desired.