kosher salt, black pepper, and other seasonings as desiredsee blog post above for suggestions
Place chicken in the bottom of the slow cooker. Position the chicken so it's in a single layer and season, if desired (see blog post above for suggestions).
Cover and cook medium boneless, skinless chicken breast on LOW for 1 1/2 to 2 1/2 hours (for other cuts of chicken, such as boneless things, or bone-in chicken breasts or thighs, and for cooking times on HIGH, see the blog post above).
Check the chicken for doneness with an instant-read thermometer. (If you're using bone-in chicken, don't touch the thermometer to the bone.) The chicken should be 165 degrees F (I remove mine 5 to 10 degrees early, since the temperature will rise as it rests). Remove the chicken to a plate or cutting board and let rest 5 to 10 minutes so the juices can reincorporate (if you plan to shred the right in your slow cooker, you can let it rest there).
When the chicken is cooked through, shred it using a hand mixer, two forks, or your fingers. Serve as desired.
For cooking times based on the type of chicken, please see the instructions listed in the blog post above.
TO STORE: Place shredded chicken in an airtight storage container in the refrigerator for up to 4 days.
TO REHEAT: Gently rewarm plain shredded chicken in the microwave until hot, topped with a splash of water or chicken broth to keep it from drying out. If you're serving sauce with your chicken, you can reheat it the chicken in the sauce on the stovetop over medium-low heat.
TO FREEZE: Store shredded chicken in an airtight freezer-safe storage container in the freezer for up to 3 months. Let thaw overnight in the refrigerator.