We have 4 little chickies. This is our first time raising chicks, and when they are older they will be joining our newly aquired flock. Anyways one of the four chicks has runny/foamy poop. The other stools look firm and shaped. How do I know what chick? Do I isolate the sick one? Chicks are 1 week old (about) They are 3 female black-sex-link and one unknown barred rock.