Hello! Recently my eldest hen Blackie who I've had for about 8 years now has developed, what I believe to be a cough. She coughs and sometimes extends out her neck as if she is gasping for air, then she'll be fine for a bit then start again. This goes on all day. Her appetitite hasn't changed, her droppings are healthy. She's drinking perfectly fine, she has no disacharge from they eyes or no fowl smell. Just this cough, the only other thing i've noticed is it seems to be slowing her down, so she doesn't get around the yard as quick as she usually does. Any help would be greatly appreaciated, thank you.