My 3 and 1/2 week old Americana has bloody stools x1 day. He/she is eating fine and drinking fine. Some free ranging has been happening in the last week while acclimating them to their coop/run in the afternoon (warmer in New Hampshire in the pm). They were vaccinated for Marek's Disease and Cocci by Mcmurray Hatchery and have been on organic 21% feed which I crushed with a mortar for first 3 weeks; I switched this week to a non medicated chick start generic brand. Hatchery recommended non medicated because they were already vaccinated and would make the vaccine null. Only one chick in the flock of 24 seem to have the bloody stools, but not sure if he/she is the only one. They are all supposed to be female, but I'm a newbie and waiting it out. Other things I've fed them: Cottage Cheese Plain Yogurt Cantalope accidentally 1 carnation flower?