Season the chicken breasts generously with salt and pepper. Place the chicken breasts in the bottom of a slow cooker. Add the garlic and rice. Add the lemon juice to the water and stir. Pour this mixture over the rice and chicken. Stir once to coat. Place the lid on the slow cooker and set on low for 8 hours. To plate, place a serving of the rice on each plate and top with 1 chicken breast. Garnish with fresh parsley sprigs.