It’s Temperature, Not Time
No matter how long a whole chicken is cooked on a Weber kettle barbecue, its doneness can only be confirmed with a meat/poultry thermometer. An instant read thermometer inserted between the thigh and body of a whole chicken should read at least 165 degrees Fahrenheit to ensure the chicken is fully cooked.
Grilling Times Depend on Cooking Methods
Indirect kettle cooking, which entails browning the chicken over direct heat and then isolating the heat to one side and placing the chicken on the grill opposite it, takes 45 minutes to an hour for a 3 to 4 lb. chicken. Placed on a Weber rotisserie using the same method and same sized bird takes about 60 to 75 minutes.
Many factors like the amount of charcoal, intensity of the heat, weather conditions and temperature of the raw bird affect the cooking time of a whole chicken on a Weber. The United States Department of Agriculture Food Safety and Inspection Service recommends using a thermometer to determine doneness of all poultry.