Add chicken breasts, onion, carrots, celery, garlic, chicken broth, Italian seasoning, oregano, paprika, salt, pepper, and lemon zest to the crockpot.
Cover and cook on LOW for 4–5 hours or HIGH for 2–3 hours, until chicken reaches an internal temperature of 165°F.
Remove chicken, shred with two forks, and return to the crockpot.
Stir in orzo. Cover and cook on HIGH for approximately 20–30 minutes, stirring occasionally, until orzo is al dente.
Stir in heavy cream, Parmesan, spinach, and lemon juice. Let everything warm through until spinach wilts.
Taste and adjust salt, pepper, and lemon juice. Add extra broth if needed.
Serve with freshly grated Parmesan, dill, and parsley.