I have a hen about 5 years old. She has been exhibiting respiratory symptoms for the past year. I’ve treated her before and seemed to improve however Ever since then she’s lost her voice, she shakes her head occasionally and wheezes. Her comb for the most part is bright red but occasionally becomes deep red. It doesn’t seem to affect her. She acts normal. None of my other hens in the flock have these symptoms. I’m curious what it could be and how to treat it?!