Right now our grass pollen is extremely high. My chicken started coughing and mouth breathing and shaking her head. I took her to the vet and $189 later she had to have 5 antibiotic shots and he wormed her just as a precaution. She is no longer coughing or mouth breathing, but she does have a runny nose. That is what happens to me when the grass pollen is high. I have tried Googling this but I cannot find anything. Does anybody know if a chicken can have allergies like humans?