For easy clean-up, put a cooking bag in the slow cooker.
Season the drumsticks with the Chinese five-spice powder, salt and pepper.
In a large bowl, combine the hoisin, honey, ketchup, soy sauce, garlic and chili flakes. Add chicken and toss to coat.
Place chicken in slow cooker. (Be sure to scrape all of the sauce from the bowl into the slow cooker.) Cook on low for 4 hours or until chicken is tender and cooked thoroughly.
Place cooked chicken and sauce in a large serving bowl. Top with scallions. Serve with rice or Asian noodles.