Respiratory? Or just a sick hen?

[Tattoodmama]

Long story short she’s been acting weird, staying inside the coop the last two days, which is not like her. She’s always been a loner but this is excessive. She was sleeping in nesting boxes and staying on roost. She walks fine. I never see her getting bullied, and I spent a lot of time with my chickens outside. I can also see them off my deck. Maybe I missed it.
I brought her inside yesterday because she was pressing her head down into her body, gave her snacks because she had excess urates, someone told me that’s a sign She’s not been eating. Made sure she had water with nutridrench.
Not sour crop. Not cocci. No egg bound.
Noticed she had a little bit of labor breathing. I heard her sneeze just once last night and haven’t since. Kept her in overnight.
Today she seem to be a better, heads out of her body, standing tall- so I decided to try to take her outside with the girls and I then noticed that she’s breathing heavier. As soon as I set her down her they started picking on her. My rooster tried to mount her violently. So I brought her right back inside and she is now breathing hard to where I can see her breathing laying down.
Is there a respiratory thing that I’ve missed? She’s only 16 weeks. She has never laid an egg.

Pic of Cheeks normally.

 

[oldhenlikesdogs]

It's it warmer outside? Does she wheeze or have any discharge from her mouth of nostrils?