Arrange oven racks in top and bottom thirds of oven. Heat to 225°F. Make 6-inch bone template and trace onto 2 large sheets parchment paper, leaving 1 inch space on each side of stenciled bones. Line 2 large baking sheets with the paper, stenciled side down. In medium bowl, with mixer on medium speed, beat egg whites and pinch salt until foamy. Add cream of tartar; beat on medium-high until soft peaks form. Add sugar, 1 tablespoon at a time. Beat until meringue stands in stiff, glossy peaks. Beat in vanilla extract. Transfer meringue to large disposable piping bag and snip off end. Using stencils as guide, pipe bone shapes onto parchment. Turn oven off. Place meringues in oven 1 hour with oven door closed. Remove from oven; cool completely. Cookies can be stored in airtight containers at room temp for up to 2 weeks.