I found the perfect chew sticks for Violet. 
 
They are called Himalayan Chew sticks. 
Check out: 
Himalayan Dog Chew - 100% Natural. Authentic. No Preservatives. An Everest Sized Treat 
They are made of solidified cheese, all natural, no preservatives. Violet is an avid chewer and she can chew on these for hours (if I let her). They come off in tiny shaving. The stay hard, to not yet mucky, or mess up her face and cheek hairs. You will love these!