I have had my chicks for a week now. They are 4 and 5 weeks old, all purchased from the same farm and were in the same pen. The smallest one, 4wks, for the past couple of days now, has had an occasional sneeze. Otherwise he/she seems fine. Eating normally, pooping normally, everything else is normal. No runny nose, no crusties, nothing. He/she is kinda timid, and every so often will find a nice place to sit down and will sit there for a few minutes watching the other chicks, but then will get back up and is back to normal activity. I'm not sure if that has anything to do with it or not, but I thought I'd mention it. Preening like normal, also. He/she definitely has enough pep to make me chase him/her forever at night to put them back in their brooder. HATES being touched. Should I be worried? Maybe it's not even a sneeze that I'm hearing, who knows.