Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente.

Drain the pasta in a colander and rinse under cold water to cool.

In a mixing bowl, whisk together the olive oil, red wine vinegar, dried oregano, garlic powder, salt, and black pepper until well combined.

In a large mixing bowl, combine the cooked pasta, diced chicken, cherry tomatoes, cucumber, red onion, and bell pepper.

Pour the dressing over the pasta mixture and toss to coat evenly.

Add the crumbled feta cheese and chopped parsley, and gently mix.

Chill in the refrigerator for at least 30 minutes before serving to allow flavors to meld.

Serve cold or at room temperature.