We have an older Maran hen who is having difficulty breathing. She is still eating and drinking. She occasionally makes a wheezing sound. I see her puffed up in a corner sometimes like a sick chicken, but if I throw treats or it's feeding time, she always comes running. What's odd is how intensely red her face and crest are - like not healthy bright red, but super dark red and not her normal color. I have been giving her some olive oil at night in case something is stuck, but no change yet (I've been doing this for about 4 days). About a month ago, I noticed her make some sneezing noises while she ate that sounded different than normal chicken-sneeze noises while feeding on mash, but I don't recall her being so red, so this is surely getting worse. No other chickens are exhibiting these symptoms. Advice?