3 week old chicks, there are 7 of them. At least one of them has had runny-ish poo since hatch. This is a pic of today's poo, the size is about a quarter. There are wood chips and pine pellets as the litter. I wouldn't call it bloody (I looked closely, and there is no odor either), but it is a light reddish brown. They have been indoors in our home, away from any other chickens, since incubation. They started on unmedicated feed and are unvaccinated. With the runny poo from some of them I switched to medicated feed after a week. I also have added grit to their medicated chick crumble. And started adding a bit if apple cider vinegar to their water. (All suggestions I read on here). I was discouraged to see this plop today. Should I be worried? All the chicks are bright, active, healthy looking and growing. They are eating and drinking normally and i clean their waterer daily and also scoop their poop daily. Any other suggestions?