Preheat oven to 400°F (200°C).
In a small bowl, combine lemon juice, lemon zest, minced garlic, olive oil, dried thyme, dried rosemary, dried oregano, salt, and pepper.
Place chicken thighs in a large resealable plastic bag and pour the marinade over them. Seal the bag and massage the marinade into the chicken. Marinate in the refrigerator for at least 30 minutes, or up to overnight.
In a large bowl, combine halved baby potatoes, trimmed asparagus, sliced red and yellow bell peppers, and sliced red onion. Drizzle with olive oil, salt, and pepper, and toss to coat.
Spread the vegetables on a baking sheet in an even layer.
Remove the chicken thighs from the marinade and place them on top of the vegetables.
Roast in the preheated oven for 40-45 minutes, or until the chicken is cooked through and the vegetables are tender, flipping the chicken halfway through cooking.
Remove from the oven and let it rest for a few minutes.
Garnish with chopped fresh parsley before serving.