I have 8 chicks ranging from ages of close to 2 weeks to 3+ weeks, and various breeds. One of the youngest one started sneezing last week and it sounded more like a "quack." That only lasted a few days, and there were a few days without any problems from any of the chicks. Now, 3 or more are sneezing. Everyone acts fine. (eating, drinking, chasing bugs, eating sand and bathing in it) They live outside in a small hutch with a heat lamp, and when the nights are in the upper 40's, I try to cover the sides up extra good. (which I do every night anyways) When it rained, I put a tarp around the outside, (the hutch is not where it will get wet) and there was cardboard underneath that to keep some heat in. On the other end, there was a gap to let air out, as well as some air coming up from the bottom of the cage. It has a wire bottom, but there is hay for bedding. As far as I know, there is not any nasal discharge from them, but honestly I don't know exactly what that looks like. I'm concerned about the air coming through the hutch. What is too much? How much ventilation is needed? Should I worry about the sneezes????