The outer hoof wall should be at least two times greater than the width of the white line, and the white line should bond with no deep cracks between the connecting sole. Weak cracking of outside wall due to extremely wet or dry conditions.
Horses have a great capacity to adapt to environmental changes.
However, it must be gradual. Sometimes horses need a little help. Sole bruising often results from constant, abusive use of horses on rocky uneven surfaces. A pick a day will be a very small price to pay. Advance cases of thrush are life threatening to your horse.