Preheat oven to 350F. Coat a 2-quart casserole dish with cooking spray; set aside. Bring chicken broth to a boil in a medium saucepan over high heat. Boil until liquid reduces to 1 1/2 cups, about 20 minutes.

Meanwhile, coat a large nonstick skillet with cooking spray and set pan over medium-high heat. Add sausage and sauté 3-5 minutes, until no longer pink, breaking up meat into pea-sized chunks as it cooks. Add onion and celery and sauté 2 minutes. Add parsley, sage, thyme, oregano, salt and pepper; mix well. Cook 1 minute, until herbs are aromatic. Place sausage mixture in a large bowl; add bread cubes and chicken broth and toss to combine. Spoon into prepared casserole dish and bake, uncovered, 30 minutes, until top is golden brown.