Cut through the thickest part of chicken breast and if the flesh is solid white and no longer pink that means the chicken is fully cooked. Another thing to look out for is the colour of the juices when the breast is cut. If the juices are slightly pink that means it needs to be cooked a little more. A more scientific approach is by measuring the internal temperature. Chicken is cooked when its internal temperature hits 74°C/165°F or higher.