Preheat the oven to 425 degrees F and line a large baking sheet with parchment paper or foil for easy cleanup.
Place the halved potatoes, carrot chunks, and parsnip chunks in a large bowl. Add the olive oil, rosemary, thyme, minced garlic, salt, and pepper. Toss until the vegetables are evenly coated.
Spread the seasoned vegetables in a single layer on the prepared baking sheet, leaving space in between for the chicken.
Nestle the chicken thighs among the vegetables, skin side up. Sprinkle the remaining salt and pepper over the chicken.
Roast for 35 to 40 minutes until the chicken reaches an internal temperature of 165 degrees F and the vegetables are tender when pierced with a fork.
Remove the pan from the oven and let it rest for 5 minutes before serving.