For the dressing; in a bowl whisk together all ingredients until well blended adjusting amount to taste, then refrigerate until ready to use (the dressing may be made up to a day in advance).
Boil the pasta shells in boiling water until al dente; drain and rinse under cold water; place into a large bowl.
Add in onions, bell peppers, celery (if using) feta cheese, olives, tomatoes and cooked chicken; toss with a wooden spoon to combine.
Add in the prepared dressing; toss well to combine.
Add in Ranch dressing (start with 1/2 cup and add in more to taste).
Add in more oregano if desired and season with salt and lots freshly ground black pepper.
Cover and chill for 5 hours or more before serving.

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Nutrition Facts

Per Serving Per 100 g

Amount Per 1 Serving
Calories	560.04 Kcal (2345 kJ)
Calories from fat	375.92 Kcal
		% Daily Value*
Total Fat	41.77g	64%
Cholesterol	74.23mg	25%
Sodium	1481.57mg	62%
Potassium	393.61mg	8%
Total Carbs	29.34g	10%
Sugars	4.64g	19%
Dietary Fiber	1.94g	8%
Protein	18.28g	37%
Vitamin C	31.2mg	52%
Vitamin A	0.6mg	20%
Iron	12.1mg	67%
Calcium	192.6mg	19%

Amount Per 100 g
Calories	199.73 Kcal (836 kJ)
Calories from fat	134.06 Kcal
		% Daily Value*
Total Fat	14.9g	64%
Cholesterol	26.47mg	25%
Sodium	528.37mg	62%
Potassium	140.37mg	8%
Total Carbs	10.46g	10%
Sugars	1.65g	19%
Dietary Fiber	0.69g	8%
Protein	6.52g	37%
Vitamin C	11.1mg	52%
Vitamin A	0.2mg	20%
Iron	4.3mg	67%
Calcium	68.7mg	19%

* Percent Daily Values are based on a 2000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
Find out how many calories should you eat.