The first step in preparing a whole chicken for slow cooking is to clean it thoroughly. Remove any giblets and excess fat from the chicken cavity, then rinse the bird inside and out with cold water. Pat the chicken dry with paper towels.
Mix the paprika, garlic powder, onion powder, thyme, rosemary, salt, and black pepper together in a small bowl. Rub this seasoning mix all over the chicken, making sure to cover every inch of the bird. You can also season the inside of the chicken cavity.
Place the lemon wedges, chopped onion, and minced garlic inside the chicken cavity. This will infuse the chicken with extra flavor and aroma as it cooks.
Place the chicken in the slow cooker, breast side up. Pour the chicken broth over the chicken.
Cook the chicken on low heat for 6-8 hours or on high heat for 3-4 hours. The cooking time will depend on the size of the chicken and the heat of your slow cooker. Make sure that the internal temperature of the chicken reaches 165°F (74°C) before serving.
Once the chicken is cooked, carefully remove it from the slow cooker and place it on a platter. Let it rest for 10-15 minutes before carving. Serve the chicken with the juices from the slow cooker and your favorite sides.