Rub the whole chicken with olive oil, then season it generously with salt, black pepper, garlic powder, onion powder, paprika, and dried thyme, making sure to coat the inside of the cavity as well.
Stuff the cavity of the chicken with the halved lemon, crushed garlic, and quartered onion.
Place the carrots and potatoes in the bottom of the crockpot. Pour the chicken broth over the vegetables.
Carefully place the seasoned chicken on top of the vegetables in the crockpot.
Cover and cook on low for 6 to 8 hours or on high for 4 to 5 hours, until the chicken is cooked through and reaches an internal temperature of 165°F.
Once cooked, carefully remove the chicken from the crockpot and let it rest for about 10 minutes before carving.
Serve the chicken with the cooked vegetables and spoon some of the broth over the top for added flavor.