I have a variety of specialty layers that are 4 weeks old. Some of them have had runny stools since they arrived. Today I saw one poop and the stool was dark brown with pinkish blood in it. Since they were vaccinated for coccidiosis and Marek's at the hatchery I am not using medicated crumble. Should I do a "wait and see" or should I treat with corid? And then do I need to buy medicated food too. All the chicks seem healthy. I have been putting them on the backyard grass when the days are warm enough while I change their shavings, food and water. I have had older chickens for a couple years but never chicks. Please help, it's the weekend and the hatchery is closed also my vet.