Put the chicken and onions in a large stock pot and brown lightly over a low heat while stirring. Stir in the water and remove the frying residue from the bottom of the pan. Bring to the boil and skim off the resulting foam. Add the remaining ingredients, cover the pot and let it simmer gently for 3 hours. Strain the broth, let it cool and put it in the fridge. Remove the layer of fat from the surface. The finished broth should soon be further processed or consumed or frozen in portions. It can be stored frozen for up to 6 months.