Our Healthy Dog Treats, Based On 100% Chicken Liver, Are All Natural With No Additives Or Preservatives. They Contain Only Real Chicken Liver. Cut Into Chunks Which Are Perfect For Rewarding Your Pet. These Freeze-Dried Treats Have A Long Shelf Life Compared To Fresh Chicken Liver, Which Means You Can Keep Them In The Cupboard And Come Back To Them Over And Over Again. Chicken Liver Naturally Contains selenium. Selenium helps to prevent and manage cardiovascular conditions such as heart disease, stroke and high cholesterol.