My 28 Cornish X are 4 weeks old and the past couple days I have noticed bloody stool. It looks to be only one, but I do not know which. All of them are running around and eating fine, with no symptoms. Currently I am feeding them medicated chick starter with 20% protein from TSC. They get 17lbs a day and that is it. They are also going through about 3 gallons of water a day. They are locked in their coop at night, and let out to their kennel all day. I clean their bedding every 4 days, and fluff it every day. The only thing that has changed is I switched from a heat lamp to a white light this past weekend. Our red light died and that is all we had that night. They also will be started on a local mill's broiler mix on Friday, with 22% protein. Is there anything that I should do to prevent it from spreading? I'd prefer a natural way too.