In a large saucepan, place the chicken, onions, garlic, carrots, celery and parsley. Cover with cold water and bring to the boil.
Reduce heat and simmer 5 hours, adding water if necessary to keep ingredients covered.
Add the white wine and simmer 15 more minutes with the lid on. Strain and reserve the stock, discarding the solids. Season with salt and pepper to taste.
Use immediately, or store in the fridge or freezer.