A lot of times they'll get bloody poo from having diarrhea or constipation. Thats from the irritation of either case. You should really go to the vet to determine whats behind the constipation or diarrhea though. My guys had diarrhea last month due to a change in food. IT can be quite simple or it could be much more complicated, but a trip to the vet can rule out the complicated stuff!