To boil chicken breast properly:

• For boneless, skinless chicken breasts, boil for about 10 to 15 minutes. Thinner cutlets may be done in around 8 to 10 minutes, while larger breasts can take up to 15 minutes

• If starting with frozen chicken breasts, increase the cooking time to about 20 to 30 minutes to ensure they are fully cooked

• Bone-in chicken breasts require longer cooking, approximately 20 to 25 minutes or more depending on size

• Always start the chicken in cold water or broth and bring to a boil, then reduce to a simmer to avoid toughening the meat

• The chicken is done when its internal temperature reaches 165°F (74°C), or when juices run clear and the meat is opaque and firm

• After boiling, let the chicken rest for about 5 to 10 minutes to retain juices before slicing or shredding

In summary, for typical boneless, skinless chicken breasts, simmering for about 10 to 15 minutes after the water reaches a boil is sufficient, with longer times needed for larger, bone-in, or frozen pieces. Use a meat thermometer to confirm doneness for best results.