Place the chickens, ginger, garlic, and leeks in a stockpot and add enough well-salted boiling water to submerge the chicken by 1 in/3 cm. Return the water to a boil, turn the heat down, and cook the chicken at a temperature not exceeding 185°F/85°C.
About 15 minutes into the cooking, turn the chickens. Skim the fat off the broth and retain it for cooking the r