Place boneless skinless chicken breasts inside your slow cooker. Liberally sprinkle both sides of each breast with sea salt and ground pepper.

Add olive oil and apple cider vinegar to the slow cooker, if using.

Set your slow cooker to cook on low for 3-4 hours or high for 2 hours.

Test to make sure your chicken is cooked through. You can use a meat thermometer to be 100% sure (the meat needs to be 165°F internally). I usually just make sure all the meat is white, cooked through and pulls apart easily.

The last step is to transfer the cooked chicken to a plate and use 2 forks or a meat shredder to shred the chicken.