About this product range:~ The giant 500g special Johnston & Jeff high energy fat ball The key ingredient in fat balls is suet. Suet is pure refined animal or vegetable fat and is one of the most concentrated and easily metabolised energy foods for wild birds. It gives them instant vigour, and they love it. It’s a superb all-year-round food, and can even cope with hard frost. Our fat balls are made to our own tried and tested recipe and to the same exacting standards as our mixtures. The only other ingredients are cereals and seeds. We never use bulking materials such as sand and waste products. We love our birds and want them to be healthy.