I immediately pulled him out of the hoop house and isolated him in one half of the old brooder box. I was really worried that the next morning I would find even more sick birds. This could be devastating to the whole flock. All the time and money and energy spent for a bunch of sick and dying birds was all I could think of. I got so stressed out that I had to go on a motorcycle ride to get away and relax.
I called my 'chicken friend' Mary at "The Hen Connection" to ask her advice and she said it is most likely coccidiosis. This was not comforting news as it can easily be spread from one sick chicken to all the rest in just a few days. Thankfully I caught it early and isolated the sick chicken, and since I move the hoop house to fresh grass twice a day, chances of the other chickens being exposed to the oocysts in the sick chicken's poop is very unlikely. However I wasn't taking any chances. So I pulled the feeder out and completely cleaned it and then hosed off any poop on the roosts and corner braces of the hoop house. Then I moved the hoop house to new ground.
According to everything I read on coccidiosis, infected chickens will typically die in 5 to 6 days, or they may recover. So far my sick chicken is still kicking but his lethargy is getting worse. He won't hardly move anything but his head and does not seem interested in eating or drinking. Also he does have diarrhea as expected, however its not bloody at all, but very green. Part of me hopes he gets better, but then what would I do with him as I would be scared to put him back in with the other chickens, especially if was week and malnourished. The other part of me hopes he just dies quickly so as not to suffer too much. Only time will tell.