not in an effort to continue "beating the dead horse", but to pass on info...
it's my understanding that poultry bones, along with pork rib bones, are not suitable for canines, due to the fact they splinter when chewed (as evidenced in the feces you've observed). the potential for injury to the digestive system exists. felines, for whatever reason, don't seem to have the same issue? maybe they don't eat the bones, i'm not a cat fanatic enough to investigate, or care...
i'm moving on now...