To make a liter of chicken stock:
1 "stew chicken" or 2-3 pounds chicken parts (feet, and legs or thighs) go into a pot with 4 liters water. Bring to a boil, reduce to simmer, and skim off scum til mostly clear (20 minutes or so).
Top back up to original water line (approx 1 liter) and Add a bunch of green onions. Simmer uncovered as low as you can until liquid is reduced to desired richness (down to a liter, after approximately 2 hours). Strain.
If under a liter, top up with water to a liter.Stock can be cooled and frozen from here, or made straight into a soup.