Abstract: A clam shell style large hay bale feeder includes a rectangular frame supporting a bale holding clam shell structure with two opposing sides formed by respective sets of steel straps. The sides are attached to the support frame such that they can fold inward and outward within the frame. Each adjacent pair of straps is spaced apart a distance sufficient to form a livestock feeding station. The clam shell structure folds inward about a hay bale placed in it such that the bale is always securely clamped in the clam shell and such that feeding livestock have constant access to the perimeter of the bale as it diminishes in size. A number of different operating mechanisms are described which serve to reopen the clam shell after the bale is consumed.