1. Quarter the leek, wash very well to remove any dirt and slice into very thin strips.
2. Mince the garlic, dice the celery and the zucchini, and set aside. In a large stockpot set to medium low heat, add the olive oil, leek, garlic and celery and cook for a couple minutes until the vegetables soften. Add the broth and orzo. Bring to a boil, then turn the heat down to a simmer, add the chicken breasts and cook for 20 minutes. Remove the chicken breasts, shred using a fork and place the chicken back in the pot.
3. Add the zucchini and simmer for another 5 minutes, then turn off the heat, stir in the dill, parsley and lemon. Taste and add salt and pepper accordingly. Serve immediately

Note: if using cooked orzo and rotisserie chicken, add them to the pot just before the zucchini and continue with the rest of the recipe.