Remove casing from sausage; crumble sausage. Heat a large nonstick skillet over medium-high heat. Add sausage, onion, and celery; sauté 5 minutes or until sausage is browned and onion is golden. Add wine to pan; cook 1 minute or until most of liquid is absorbed.
Rub each side of bread with cut sides of garlic; discard garlic. Coarsely crumble bread; add to sausage mixture. Stir in parsley, 1/4 teaspoon salt, and pepper. Let stand 5 minutes or until liquid is absorbed; toss to combine.
Place each chicken breast half between 2 sheets of plastic wrap; pound to 1/4-inch thickness using a meat mallet or rolling pin. Place half of stuffing on one side of each chicken breast half, leaving a 1-inch border around sides. Fold remaining half of each chicken breast over stuffing, and secure with wooden picks. Sprinkle chicken with remaining 1/4 teaspoon salt.
Heat a large skillet over medium-high heat. Coat the pan with cooking spray. Add stuffed chicken breast halves to pan; cook 3 minutes on each side. Add chicken broth, scraping pan to loosen browned bits. Cover, reduce heat, and simmer for 5 minutes or until chicken is done. Remove the wooden picks; slice breasts in half. Serve immediately.