[cypher]

They do look a bit long, once they get overgrown then they need clipping, either do it yourself or go to the vet.
Smooth rocks aren't going to help so I wouldn't bother, for maintenance once they've been clipped rough but not sharp surfaces like wood, granite, a normal kitchen tile turned upside down, terracotta flower pots will help keep them down as will some wooden surfaces & digging in a sand bath.