Place chicken bones in a large, heavy-based saucepan or soup pot and cover with water. Add onion, carrots, turnip, celery, salt, peppercorns, parsley and bay leaves.
Cover and bring to boil on high. Reduce heat slightly and simmer rapidly for 30 minutes, removing any scum that rises to surface with a slotted spoon.
3.Reduce heat to low and cook gently for 2 hours. Season to taste.
Strain stock through a fine sieve and cool. If time permits, chill overnight, then remove any fat solids from surface.
Reheat stock in a saucepan on medium. Stir through pasta and parsley before serving.