Cut the chicken into 4 pieces. Peel and wash the vegetables. Cut the onion into 4 pieces. Cut the other vegetables into a mire poix (big cubes). Place all the ingredients in a tall pot and cover generously with water. Add the bouquet garni tight up with rope into a leek leave. Season slightly and cook on low heat during 4 to 6 hours. Skim time to time. Strain and pour through a fine sieve. Store in a refrigerated place and freeze if necessary for later use.