DRY SKIN : Dryness causes the skin to crack. Skin on the feet tends to become drier as there are no oil glands present there.  Lack of moisturization, overexposure to pollution, and some medical conditions such as eczema, diabetes, thyroid, and psoriasis lead to dry skin.  Dry layers of skin when harden and build up into thick  dry callous can eventually crack due to  intense pressure or friction on it.

Soaking, Exfoliating, Moisturizing and putting a layer that can lock in moisture is the simplest way of dealing with the dry heels or cracked heels problem.