Hi! I'm not new to chickens, but I'm new to this behavior! My Wyandotte, Wendy, is making this odd sound, constantly, as she breathes. I can't tell if it's physical pain from some trauma or maybe sickness? It just started a few hours ago. I see no visible injuries, nor do I feel anything wrong. She seems to be eating and drinking. Her eyes and nostrils are clear and I haven't seen abnormal poo. She's about 5 months old, and honestly I'm not entirely sure if she's laying yet. Her other flock mates seem to be doing fine, so I separated her just in case. I have a roo but he never seems to be very rough with his girls so I don't think it was him. They have plenty of shade and water in their run. Also she's vaccinated against Marek's. I'm stumped and also very, very concerned. 
The link is the video of the noise, I hope this is okay, because for some reason it won't let me insert it as a normal video.
https://www.instagram.com/p/CSA2jWIAMRe/?utm_source=ig_web_copy_link
I can't get her to a vet right now, so any advice from someone who may have experienced similar would be very greatly appreciated!

The link is the video of the noise, I hope this is okay, because for some reason it won't let me insert it as a normal video.
https://www.instagram.com/p/CSA2jWIAMRe/?utm_source=ig_web_copy_link
I can't get her to a vet right now, so any advice from someone who may have experienced similar would be very greatly appreciated!