Raw chicken can certainly go into a slow cooker to be cooked. There is some debate on whether it is safe to put frozen chicken breast in a slow cooker. The USDA advises against it, but slow cooker manufacturers insist that it is completely safe as long as the chicken is heated to an internal temperature of at least 165 degrees F. I personally have no problem using frozen chicken in a slow cooker, but you will have to make the best decision for your family. You can read this article for more info!