Place chicken in large soup pot with cover (I used my 7 quart nonstick Dutch oven). Add enough water to cover the chicken (about 8 cups).
Add in the onion, carrots, celery, and bay leaves. Bring to a boil and then lower heat to a low boil and begin to skim the fat (some foam should be floating to the top) off. Do this until most of the foam has been removed (could take 20 minutes more or less). Add in the salt and pepper (if using).
Add in the fresh dill and parsley (if you’re using). Continue to simmer gently for about one hour.
Taste soup and add additional salt, pepper.
Strain the broth through a fine-mesh sieve or strainer into a large bowl. Reserve the carrots. Reserve the chicken (take off the bones) if you're serving the broth with chicken.
If you’re cooking the pastina in the broth:
Strain the broth (reserve the carrots and take the chicken off the bone, if you’ll be serving it with the pastina). Bring 6 cups of chicken broth to a boil.
Add the pastina and reduce heat to a simmer for 3-4 minutes, or until al dente. Ladle into bowls and serve with pieces of the carrots. Add on some grated cheese if you like.
The other option is to cook the pastina in a pot of boiling water. Reduce heat to a simmer for 3-4 minutes, or until al dente. Strain the pastina and portion directly to bowls and ladle the broth on top.