Evenly layer the chicken thighs in the bottom of a 6-quart slow cooker insert.
In a microwave safe bowl or measuring cup, microwave the butter and flour together for one minute. Remove and stir. Microwave for 2 more one minute increments to create a microwave roux. The butter and flour will bubble up each time you microwave them.
Stir in each of the sauce ingredients until well combined - bourbon, marmalade, soy sauce, brown sugar, garlic powder, ginger, red pepper flakes and salt.
Gently pour the sauce over the chicken.
Cover and cook on low power for 6-8 hours, or until the chicken thighs easily shred or fall apart with a fork or tongs.
Serve the chicken and brown sugar bourbon sauce atop rice and garnish with green onions.