Krystal,
Anything that is slightly bigger than your dog's foot and won't tip over will work. Canned goods work well. It seems canned peaches are about the right size for some dogs
. They are heavy enough that they don't tip over. Stacking blocks can be made fairly easily using large dowel rods and any flat piece of wood for the ends. Even with a big dog, you should be able to lift each foot and place it on the blocks. The blocks should be high enough that is uncomfortable for the dog to step off of them
. Typically, bricks are too big to give the foot a definitive place. Use a mirror to see if your dog is stacked properly. I like the book "Raising a Champion: A Beginner's Guide to Showing Dogs" by A. Meredith John and Carole L. Richards.Another book you may find useful is "The Absolute Beginner's Guide to Showing Your Dog" by Cheryl S. Smith. I hope this helps you some
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Also, is there a kennel club that offers handling classes in your area?