Chicken’s breathing is squeaky and panting

[threeblueducks]

This evening my five-year-old Brahma hen’s breathing started sounding weird, sort of squeaky and wheezing. She is panting as well, which I also noticed yesterday but didn’t think twice of it as it has been unusually warm (high 60s, 70s fahrenheit). She is a disabled chicken (leg issues) but gets around almost as well as a normal chicken, though she has had a couple other health issues in the past — respiratory infection when she was young and a fungal infection on her face last summer. What could this be?

I will do some research on it but I appreciate any input that anybody has!
Edited to add: Some of the other chickens are also panting, but she is the only one whose breath sounds weird.