To poach chicken: Place chicken breasts in a large skillet. Cover with water or chicken broth. Bring to a low boil. Reduce heat and cover. Let simmer about 8-10 minutes. Remove the chicken and discard the liquid. Cut chicken into bite-sized pieces.
Whisk together the mayonnaise, sour cream, vinegar, honey, poppy seeds, salt and parsley in a large bowl.
Gently fold in the chicken, grapes, celery and pecans.