Anytime we feed our dog anything outside of his usual beef and salmon diet, diarrhea ensues. Any kind of poultry is the worst for him. You have to gradually add any new foods a bit at a time (think: spoonful) into his regular food if you want to give him more variety so he as time to adapt; then monitor closely. He had a dehydrated pig ear the other day without issue. He was supposed to gnaw for days, finished it in a thirty-min don't-even-look-at-me session.
Ps. OMG, he's so cute if the blood persists, have him examined if you can.