Early this week I noticed one of the chicks I have wasn't doing too well. Very inactive, elevated breathing, runny, light brown poo, and was drinking, but not eating. It's about 8-9 wks old. Banty cochin. I separated it from the others and put poly vi sol in its water(only thing I had at the time). It is now Sunday and the chick is back to eating but is extremely inactive. Any ideas on what this may be? What can I do?