Try buying some 6X6 inch concrete reinforcing wire and bend it into a triangle with side lengths of 18 inches, or 3 squares. Next you can customize the height to what you need, I make 3.5 foot high cages and they seem to work well for me. You will need some heavy duty wire cutters. If laid out flat you should have a 9X7 grid. Make sure to cut the squares outside the 9X7 leaving as much of the adjoined wire for connecting the third edge of the triangle and for securing into the ground. This method produces a very sturdy cage. Good luck!