Ok, we measureed my purebreed Appaloosa. Her back were 10" (length) and 12" (circumference), and her front her 9.5" all round. According to the sizing chart for SMB boots, she is a small on her front and medium on her hind. Does this sound right? Since they don't have her exact length and circumference on the chart for the same size I went for her circumference. Thank you for the help!