The Nature’s Own Dog Chews all natural dental knee caps (patella) are a great dental chew. These ALL natural dental knee caps have no additives or preservatives. Many bones have added liquid smoke(artificial flavours) or may even be deep fried. Ours are slow air dried (dehydrated) to properly preserve the flavours dogs love . No hormones or antibiotics. Your dog’s teeth will scrape against the knee cap to support proper oral hygiene. This is from free range beef.