I live in Phoenix and monsoon season has hit. After a few days of rain I noticed a few of my hens, I have 6, started to sneeze a little. Well now they've progressed to some raspy breathing, and some mucousy nostrils. What is it? The chicken equivalent of a cold or is it something more serious? And what if any antibiotics should I be giving them? And do I need to give them to the whole flock or just the ones with symptoms? 3 of them have symptoms, just not quite sure what to do.