Place chicken in a 1-1/2-qt. slow cooker. In a small bowl, combine the broth, cider, vinegar, lemon juice and seasonings; pour over meat. Cover and cook on low for 4-5 hours or until chicken is tender., Remove chicken; keep warm. Skim fat from cooking liquid. In a small saucepan, melt butter; stir in flour until smooth. Gradually add cooking liquid. Bring to a boil; cook and stir for 2-3 minutes or until thickened. Serve with chicken.