Place all the ingredients for the chicken stock in a large saucepan over medium-high heat. Bring to a gentle simmer. Reduce heat to low and simmer for 40 minutes or until the chicken is just cooked. You can test by piercing the leg joint and if the juices run clear or just light pink, then the chicken is cooked. Simmer for longer if your chicken is larger. When cooked, transfer the chicken to a plate and allow to cool. Strain the chicken stock into another clean saucepan over medium-high heat. Add the rice and simmer until the rice is broken down and the mixture is thick and porridge-like (this could take 60-90 minutes). Stir often to ensure the rice doesn’t burn. Slice and shred the chicken meat. To serve, divide the congee among serving bowls. Top with the chicken meat, ginger, spring onion and drizzle with soy sauce to taste.