I found this recipe. I made them for the pups, and they loved them. They are healthy for the pets. I have not bought any bone cookie cutters yet. I used a medium size and small size star cutter. If you don't have any cookie cutters, you can use a glass to cut dough.
Preheat oven to 375 degrees. In a bowl, combine flour and baking powder. In another bowl, mix peanut butter and milk. Add to dry ingredients and mix well. Roll dough into 1/4 inch thickness and use a cookie cutter to cut out shapes.
Bake for 20 minutes on a greased baking sheet until lightly brown. Cool on a rack, then store in an airtight container. Note: Cookies could burn easily around the edges.