The smallest of our five chooks is standing inside the coop in the light from the brooder lamp while everyone else is outside in the run. -5 is sullen, eyes half closed, and is rasping when she breathes in and out. I picked her up and checked her closely, and there is no sign of any wound, no discharges from her nostrils or vent. Nobody else shows any symptoms. This chick has always been smaller than the others and is lagging slightly behind the others in size. It was our understanding that she was the last to hatch in that clutch, and was always the smallest of the bunch. Should I be overly concerned about the raspy breathing? Should I be isolating her and treating her with something, or do I let whatever this is run it's course? What other symptoms should I be on the lookout for? She's been out eating and drinking earlier today, but she is not out running around with the others now. What to do?? Thanx!