I noticed at least 4 of my 9 chickens with a clear discharge from their nose yesterday. They are all 6 months old. Laying mostly every day. Everything else seems normal. It has been really cold and rainy here, finally today it's sunny and should be above 50 degrees! It looked to me like I do when I'm outside in the cold - a runny nose. I put some polyvisol in their water today, should I be more concerned about them? Not sure what else I can do.