Preheat the oven to 425°F. Line a large sheet pan with parchment paper or foil for easy cleanup.
Place the carrots, potatoes, parsnips, and red onion in a large mixing bowl. Add the minced garlic, olive oil, rosemary, thyme, salt, and pepper. Toss until the vegetables are evenly coated.
Spread the vegetables in a single layer on the prepared sheet pan. Nestle the chicken thighs among the vegetables, skin side up. Sprinkle the chicken with a little extra salt and pepper.
Roast for 35 to 40 minutes until the chicken reaches an internal temperature of 165°F and the vegetables are tender when pierced with a fork.
Remove the pan from the oven and let it rest for 5 minutes. Serve with lemon wedges on the side.