Season the chicken with salt and pepper. Place the chicken, onion, celery, garlic, stock and water in your slow cooker. Cook about 3 hours on high, or 4-5 hours on low, adding the rice or orzo during the last hour or so of cooking time to prevent overcooking.

When the chicken is done, remove it from the slow cooker and allow to cool slightly. Chop into chunks or shred, and place back in the slow cooker.

Place the eggs in a medium bowl and beat lightly, then whisk in the lemon juice until combined. Place about 1 cup of hot soup broth in a measuring cup, and add a few droplets at a time to the egg-lemon mixture whisking constantly to temper the eggs. Continue adding the hot broth in a slow, steady stream while whisking constantly.

After all the stock has been added, add the egg-lemon mixture to the soup in the slow cooker and stir to combine. Season with salt and pepper to taste, serve, and enjoy!