In 4- to 5-quart slow cooker, place turkey; sprinkle with garlic-pepper blend and salt. Add remaining ingredients except half-and-half and cornstarch; mix well.
Cover; cook on Low heat setting 6 to 8 hours.
In small bowl, mix half-and-half and cornstarch until smooth. Gradually stir into chowder. Increase heat setting to High. Cover; cook about 20 minutes longer, stirring occasionally, until thickened.