Sarah,
I worked outdoors most of my adult life. Most winters I was bothered with cracked heels and sometimes cracked soles. Once I started on natural cures I did a lot of experimenting and came up with something that will heal the cracks.
I take a pint of any good lotion and add about 1/2 cup of a good oil---olive oil, sesame oil or most any kind. Seems that the sweating of the feet dries the skin out and a daily rubbing in of this adds the oils back. If kept up regularily the bottoms of the feet will be like baby smooth soft skin.
This same stuff will also work for chapped hands or any dried skin.