Add the chicken breasts (or thighs) to the slow cooker. Sprinkle over the salt, pepper, garlic powder and lay over the bay leaf and butter.
Pour over the chicken broth.
Place the lid on the slow cooker and cook on low for 6-8 hours or on high for 3-4. If you use frozen chicken breasts, keep the lid on the entire cooking time and cook for 8 hours on low or 4 hours on high.
When the cooking time is done, drain off a majority of the chicken broth (save the broth if you are going to freeze the chicken), leave about a half cup in the slow cooker with the chicken. Shred the chicken with 2 forks or use a hand-held mixer and use the beaters on low speed to shred the chicken.
Use the chicken in your favorite recipe and enjoy. Refrigerate for up to 3 days.