Whisk together the yogurt, mayonnaise, lemon juice, salt and pepper until smooth. Add in the Poached Chicken, celery, grapes, raisins and apples. Mix until the salad is coated in the dressing. Line the bottom of four serving bowls with 3 leaves lettuce. Divide the salad evenly among the bowls, over the lettuce. Sprinkle the walnuts on top of the salads and finish with the chives to serve.
Place the celery, onions, carrots and wine in a large saucepot set over medium-high heat. Bring to a simmer and cook until the liquid reduces by half, 5 minutes. Add the chicken, and then pour enough stock to cover, adding more if needed. Bring to a simmer and cook until the meat falls off the bone, 30 to 45 minutes.
Remove the chicken to a baking sheet and cool. Strain and reserve the broth for another use, like a soup or sauce. Cool the chicken, then shred the meat.