Absolutely she needs supplements if she is primarily eating a home cooked diet. Getting the calcium to phosphorus ratio is critical as if it is not right, Ruby can develop skeletal, cardiac and neurological issues.
Calcium & Phosphorous in Dogs* - Chinaroad Lowchens of Australia -
Dogs on a homecooked diet need bloodwork after six months to make sure they are getting the proper nutrients and regular bloodwork thereafter.
Either consult a nutritionist or follow a diet prepared by a nutritionist that includes the supplementation exactly.