Combine teriyaki sauce, hoisin sauce, honey, and orange marmalade in a slow cooker. Stir to combine.
Add chicken drumsticks to slow cooker and press down so they are covered with sauce.
Cook on low for 3-5 hours.
Preheat broiler.
Remove chicken from slow cooker and place on a cookie sheet. Bake under broiler for 2-3 minutes per side to crisp up the chicken.
Sprinkle with green onions and sesame seeds.
If preparing in oven:
Bake chicken at 350 degrees F for 1 hour, turning pieces over and basting with pan juices after 30 minutes. Sprinkle with green onion and sesame seeds before serving.