Bloody poo is certainly alarming and reason to do further investigation. Here are a few things: it could be giardia, an intestinal protozoan (dogs drink dirty water, ingest giardia from another animal who has pooped nearby and had giardia). Giardia can cause off and...
You gotta ask WHY does my dog have low thyroid? Did your veterinarian run the full panel (T3, T4, free T3, free T4, TGAA that gets sent off to another lab, ideally Hemopet http://www.hemopet.org/index.php?option=com_content&view=article&id=24&Itemid=39 or...