Question: how long do chicken breasts take to cook at 400 degrees?
Answer: Baking times vary depending on the size and thickness of the chicken. A medium size chicken breast (5 to 6 ounces each), takes approximately 20 to 25 minutes to bake in a 400 degree oven. I always bake chicken breasts at 400 degrees Fahrenheit as the high temperature helps seal in the juices (and the flavor).