One of my oldest hens has very labored breathing today, she seems to be really having a hard time. Poop is normal, she has showed signs of wanting to eat and drink and other than here breathing hard she seems normal. I don't want to just give her antibiotics if they are not needed but I feel like I need to do something. She was wormed with Valbazen over a month ago and has not had any change in feed. Her eyes are bright and she is not molting. Any thoughts?