The recipe I always use for dog biscuits is cut some liver (whichever kind is the cheapest) into chunks and bring to boil in water until just cooked. Then cut into small dice or mince the meat, add the cooking water, and enough wholemeal flour to make a firm dough. You can also add some oil, or eggs as well, depending on your budget. Shape into biscuits, put onto trays and bake at 180 until hard. These keep well, but if a bit soft you can put in the fridge. You can also mix them in a food processor. – LG, Warkworth.