Preheat oven to 300 F. Lightly grease 2 large baking sheets or line them with parchment. Mix the flour, oats, parsley, dried milk, and salt. Add eggs and peanut butter, stirring to combine. The mixture will be quite crumbly. Add just enough water to bring the dough together, roll the dough out to 1/4 – inch thickness on a floured surface, then cut out biscuits with a cookie cutter of your choice. Gather and re-roll the scraps, continuing to cut biscuits until all dough is used. Bake for 40-60 minutes until golden brown and crisp all the way through. Remove from oven and allow to cool on the baking pans.