Combine the first four ingredients, mix well. Dissolve the bouillon cubes in boiling water. Add bouillon mixture to flour mixture to make a stiff dough. For different flavors, add any of the following: garlic, crisp bacon strips, bacon drippings or your dog's favorites. Roll onto a floured surface. Cut out shapes with a cookie cutter or glass. Bake in a preheated 300F oven for 30 minutes. Let stand overnight to harden better.