Raw meaty bones, straight from the butcher (our butcher is like an old timey German family, actually....the Dvoraks! Dressage people may know haha). Usually Bison, because the vet said beef was a common meat to be allergic to, and gamey meats tend to be more tolerable with dogs with allergies. I think they are slices of a large bone, they end up being like fist sized rings.