Wild Eats® Collagen Pretzel Duck Flavor Dog Treats. These chews feature beef gelatin, a cooked form of collagen, as the number one ingredient. Collagen supports strong joints and muscles. It also promotes a healthy coat. Wild Eats collagen is hydrolyzed to help break down the dermis layer, making each chew easy to digest. They come in a fun pretzel shape and are a tasty alternative to bully sticks and rawhide treats.