Some of our chickens are showing symptoms of upper respiratory infection (sneezing, trouble breathing, and a little bit of clear discharge from the nostrils.) and I'm still new to owning chickens so I don't know how to treat it. Other than the sneezing and a little trouble with breathing they seem to be fine. They're eating and drinking and running around just fine. I had someone tell me to just put electrolytes and vitamins in their water so I've been doing that for the last couple of weeks and it seemed to help some but not much. Is there anything else I can give then to help them fight off what ever it is they've come down with?