We are new to chicken keeping and have had some issues with coccidiosis. We got 4 chickens a month ago (buff orpington and banty light brahma, 20 weeks old, silver laced wyandotte and ameraucana 14 weeks old). 2 came from one person, the other 2 came from somewhere else. They were enclosed in a 7 by 4 foot coop that had not had chickens previously. Their run was not finished for a few weeks, so this is where they stayed, with small runs added occasionally. I wonder if being a small space and the stress of a new home brought this on. 12 days ago the buff began acting ill, lethargic, falling asleep standing up, sleeping during the day with her feathers ruffled up. Within a few hours I put everyone on Corid and gently syringed some medicated water into her mouth. I also switched everyone to medicated chick feed, as I was unsure what was wrong for sure. She was no worse the next day and was showing signs of improvement. After 3 days she was back to normal. I couldn't find a chicken Corid dose, so I did give too much now that I know the real dosage (5 ml/gallon). I gave 7-10 ml/gallon for 6 days. I noticed even though none of the others acted sick, there was bloody poop under the roost. It is firm, but definitely bloody. The man at the feed store suggested I switch to Sulmet, so I did, with no break. I followed the label, 29 ml/gallon for 2 days, 14.5 ml/gallon for 4 days. I am still seeing bloody poop every morning and I finally took a sample into a vet to make sure it was coccidia. It came back positive with 50 oocytes/gram. I have no idea what this value means exactly and my report was sent after hours the Friday of a 3 day weekend. I have been raking the straw out of the coop every day and also cleaning the roost to try and keep the numbers down. We are considering torching their entire run, since we can't move it easily. Their run is grass. A different man at the feed store suggested putting them on Corid again. Today is day 1 of 5 ml/gallon, I was planning on treating for 7 days. I am frustrated that this is not clearing up and not sure what to do next. Are there other drugs I can try, or alternative treatments? I have read something about apple cider vinegar. Will my chickens die if left untreated? I added a picture of the poop (not that you can miss it!). Does anyone have experience with coccidia not responding to treatment?