The pig's hoof is characterized by sudden changes between hard and soft horn and a high growth rate of the horn wall. These facts contribute to the high incidence of hoof alterations, which is seen in various inadequate floors. Hoof alterations are only painful in cases, where the corium is irritated. Some hoof alterations are described, the question of poor footing is discussed. The author provides recommendations regarding the recognition of inadequate barn floors and their improvement. Stable claws develop in animals housed on floors with soft surfaces or under restricted movement. Hoof cracks or soft heel ulcers are frequently seen in animals housed on rough and abrasive floors. Slatted floors with wide gaps and sharp edges cause a high rate of lesions at the coronary border. The construction of slatted floors should be done with respect to the size of the hooves, which is related to the body weight. For prevention of lesions the gaps should not exceed the given values.