Equipment: Cookie sheets lined with parchment or aluminum foil; rolling pin; 3-31/2" bone cutter or 2 1/2" round cookie cutter. Place 2 oven racks in the upper and lower thirds of the oven. Preheat oven to 300F. Sprinkle the dry yeast or crumple the compressed yeast over the water (110F if dry yeast, 100F if compressed yeast). Add a pinch of sugar and allow the yeast to sit in a draft-free spot for 10-20 minutes. The mixture should be full of bubbles. If not, the yeast is too old to be useful. In a large bowl, place all the dry ingredients and stir to blend them. Add the yeast mixture and 3 cups of the broth. Using your hands, in the bowl, mix to form the dough, adding more broth if needed to make the dough smooth and supple. Half a batch at a time, knead the dough briefly on a lightly floured counter. (Keep the second batch of dough covered with a moist towel while shaping and cutting the first.) Roll out the dough into an 18 x 13 x 1/4" rectangle. Cut it into desired shapes, using a 3 3 1/2-inch bone cutter or a 2 1/2-inch round cookie cutter. Reroll the scraps. Repeat the procedure with the remaining dough. For an attractive shine, lightly beat together the egg and milk. Brush the glaze on the cookies. Bake for 45 to 60 minutes or until brown and firm. For even baking, rotate the cookie sheets from top to bottom three quarters of the way through the baking period. Use a small, angled metal spatula or pancake turner to transfer the cookies to wire racks to cool completely. Store in an airtight container at room temperature. The dough must be used immediately. The baked cookies will keep for many months. Allow cookie sheets to cool completely between batches.