A 5-pound chicken typically needs to roast for approximately 115 minutes at 350 degrees Fahrenheit to be fully cooked. This applies even if the chicken is cooked at high heat to get extra crispy skin.
According to AllRecipes.com, chicken should be roasted for 20 minutes per pound, plus an extra 15 minutes. To ensure the chicken is fully cooked, a meat thermometer inserted into the chicken's inner thigh should read at least 165 degrees Fahrenheit before serving. After the roasting is finished, the chicken ideally sits under a tent of aluminum foil for 10 minutes to let juices redistribute throughout the bird, keeping the meat moist.