Preheat your oven to 425° F and place a rack on the lower middle position.
Preparing the chicken: Using kitchen shears, cut up the back of a whole chicken (remove giblets) on both sides of the backbone, removing it completely. This allows the chicken to be spatchcocked, or butterflied, so both breasts face up.
Add a few slices of oranges to the bottom of a large, high-walled baking dish (18x13x2-inch size works well for roasting). Place the chicken on the orange slices in the center of the dish, breast side up. Rub the chicken well with 1 tablespoon of olive oil and season with a pinch of salt, pepper, and thyme (approximately 1/2 teaspoon each).
Toss the cut-up parsnips, carrots, and potatoes with the remaining olive oil and spices, and spread them around the chicken in the baking dish. Add the remaining orange slices to the dish around and/or on top of the chicken.
Bake the chicken for 20 to 25 minutes until the skin starts to brown nicely. Then, turn the heat down to 375° F and roast the chicken until it reaches an internal temperature of 165° F in the thickest part of the breast, about another 30 to 35 minutes. Use a meat thermometer to make sure it's cooked through.
Once you turn the temperature down to 375° F, brush the chicken with orange honey glaze, and then do so again midway through roasting.