The short answer is yes. If you’re feeding your ferrets a protein-rich diet such as Marshall Premium Ferret Diet, they are getting a majority of the nutrients they need, but it’s always good to use a daily supplement for optimal health and well being. Supplements help maintain a shiny coat and prevent dry skin as well as boosting immunity. High calorie supplements, such as Furo Vite are particularly helpful when a ferret is recovering from illness and needs to gain weight.