In a small bowl, whisk the egg with avocado oil and sparkling water.
Stir in the matzoh meal, sea salt, and black pepper until combined; refrigerate for 20 minutes to firm up.
In a large pot, bring the chicken bone broth to a gentle simmer over medium heat.
Add the chicken breast and poach for 15 minutes until cooked through; remove and shred.
Add diced carrots, celery, and onion to the broth and cook for 8 minutes until slightly softened.
With wet hands, form the matzoh mixture into 2 to 3 small balls and carefully drop them into the simmering broth.
Cover the pot tightly and simmer for 20 minutes; do not lift the lid to ensure the balls stay fluffy and airy.
Return the shredded chicken to the soup, stir in fresh dill, and serve hot in a deep bowl.