Our basset Mazy is a shelter rescue and was under weight when we got her. Our vet says she is around 4yrs old and she was already spayed before we adopted. We have tried different foods and diets,but it seems that she just won't put on any weight she has heart worms and is on treatment. We have 2 other basset hounds that are fat and healty. If you can give me any advice as to how to put weight on her we would really appriciate it.