Some dogs just have crappy nails. Paxil's nails split, crack and break all the time. The musher I got her from says her nails have always been like that. When I adopted her, that was one of the things she made sure to point out to me. I keep Paxil's nails as short as possible.

You can buy supplements that are supposed to help with foot and nail health. You might want to check at your local feed store.