What does it mean for a heel horse to read the corner?

Reading the corner means the heel horse understands and anticipates the shape, pace, and timing of the header's turn well enough to arrive at the delivery position without being steered there step by step. A heel horse that reads the corner tracks the header through the arc, adjusts its own speed to match the pace of the turn, and arrives at the correct angle and distance from the steer's hind feet at the moment the heeler is ready to deliver — all without the heeler needing to manage the horse's position while simultaneously timing the loop. The horse that does not read the corner requires constant rider adjustment through the turn: pull back here, push up there, move left, move right — and by the time the heeler has managed the horse through the corner, the shot has changed or the moment has passed. Reading the corner is developed through repetition on varied cattle and varied corners, not through drilling a single consistent run. A horse exposed only to fast headers making tight turns will read that corner well and be late or lost behind a slow header making a wide turn. Exposure to headers of different speeds, turn styles, and cattle of different sizes and behaviors teaches the heel horse that corners come in many shapes and that its job is to read each one as it develops rather than anticipating a fixed pattern. The rider's role is to stay balanced and out of the horse's way when it is reading correctly, intervening only when the horse drifts significantly off the correct lane. A heel horse that genuinely reads the corner is one of the most valuable attributes in a finished team roping horse because it frees the heeler's entire focus for the delivery.