Hi, I have a black Australorp roughly 4 years old that has developed a swollen nostril on just one side. Over the course of about 2 weeks its gotten slowly, steadily worse. The other side is totally normal. No discharge or other noticeable symptoms. I've been cleaning it daily and applying some VetRx, but no change. Any idea what it might be? Pictures below show the normal side and the abnormal side (with a little food on the beak too).