Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.
In a large mixing bowl, combine the cooked pasta, shredded chicken, celery, red bell pepper, and red onion.
In a separate small bowl, whisk together the ranch dressing and buffalo sauce until well combined.
Pour the dressing mixture over the pasta and chicken mixture. Toss gently to coat all ingredients evenly.
Add the blue cheese crumbles and season with salt and pepper to taste. Toss again to combine.
Cover the salad and refrigerate for at least 30 minutes to allow the flavors to meld.
Before serving, give the salad a gentle toss and garnish with chopped parsley.