Cook time will vary based on temperature and cooking method. If you bake the chicken thighs in the oven, you should roast them for 40 to 50 minutes at 350 degrees Fahrenheit. Or 25 to 30 minutes baked at 425 degrees Fahrenheit. If you cook chicken thighs on a grill, they should be grilled for approximately 6 to 7 minutes per side at medium-high heat (between 400 to 450 degrees F), or until the thickest part of the thighs reads 170-175 degrees Fahrenheit on an instant read thermometer.