We soon noticed that the rooster had a runny "nose". By the next day, half my flock was acting sickly as well (runny nose, wheezing, sneezing, not eating much, not very active). Most of them recovered in a couple of days, but I have one hen (Buff Orpington) that is really struggling. She has been gasping for air for the last 4 days, and I hate to see her struggling like that.
She is gasping. Standing or lying down, she stretches out her neck and opens her mouth wide to get a breath. Then does that again with every breath. I just ordered some Tiagard based on another thread
Sorry to hear she's not doing well.I’m so sorry to hear about your chicken. I do not have experience with respiratory issues, so I am going to tag some folks for help. @Wyorp Rock @Eggcessive @azygous
For now, I agree on the electrolytes and supportive care. Get her somewhere warm if you can, a crate inside maybe if it isn’t too stressful.
Since the others have all recovered and doing fairly well now, I wonder if she may have something else going on in addition to respiratory infection.
What does her crop feel like, any lice or mites, when was her last egg, does she have any bloat or feeling of fluid in the abdomen below the vent between the legs?
Mycoplasma does come to mind, if that is what is affecting her, then the Tiagard (Tiamulin) should help with symptoms. Tiamulin is very bitter, so sweeten it with juice or Karo Syrup, follow the dosing on the bottle.
Tylosin is also commonly used to treat symptoms of MG, I've included a link below if you wish to get some of that.
https://jedds.com/products/tylosin-powder?_pos=1&_sid=a59697554&_ss=r