Place the chicken and peppercorns in a large skillet. Pour water over to cover just above the chicken. Bring to a boil over medium high heat. Lower the heat, cover and simmer for 10 minutes until the chicken is cooked through. Remove the chicken with a slotted spoon to a plate to cool. Discard the poaching liquid.
In a large bowl, combine the grapes, apples, celery, apricots, cherries, scallions and red onion. When the chicken is cool enough to handle, cut into cubes.
Add the chicken, mayonnaise, salt and pepper to the grape and apple mixture. Mix well. Serve at room temperature.