My 6-month-old rooster Lew has been sneezing and wheezing all day, and it is getting worse. None of my other chickens are showing symptoms. We recently got some new birds from an auction, but they were quarantined for a few weeks before being introduced to our flock, and none showed strange symptoms. They've all been together for over 2 weeks. Our flock has been totally healthy before now, and Lew seemed fine until this morning. I've got him isolated and have put antibiotics in his water, but he seems too sick to eat or drink. I've attached a video...If anyone can tell me what this is or what I should do about it, I would really appreciate it!