Combine chicken, stock, water, onion, green onion, bay leaf, thyme, 2 tbsp coriander, and peppercorns in a Dutch oven or stockpot.

Bring to a boil over high heat.

Reduce heat, cover, and simmer until the chicken is fork-tender, about 1.5 hours.

Remove the chicken from the broth and let it stand until cool enough to handle.

Cut the chicken meat into bite-size pieces; discard the bones. Skim off any excess fat from the broth.

Strain the broth into a large bowl and then return it to the Dutch oven.

Add the potatoes and bring to a boil over high heat.

Reduce heat, cover, and simmer until the red potatoes are tender, about 1 hour.

Add the reserved chicken and corn.

Cover and continue simmering until the corn is tender, about 30 minutes.

Add salt and pepper to taste. Stir in 3 tbsp of capers and 1/4 cup of half and half. Add the remaining 2 tbsp of coriander.

To serve, transfer the soup to a large tureen.

Ladle the soup into individual bowls.

Sprinkle each portion with some of the remaining capers and top with a spoonful or two of the remaining half and half and some cubed avocado.

Serve immediately.