2 wk old Chick respiratory issue?, do I separate her?

[Blessedmamaof3]

I have a chick that is almost 2 weeks old. I got her yesterday and soon after noticed her open mouth heavy breathing. Seems to keep her awake at night. When I hold her close, I can hear a rattling sound. Im assuming this is something respiratory. When I picked her up from seller, the brooder was in the living room with a couple people in the room smoking . I'm assuming that cant be good for baby chicks and wondering if it could have anything to do with her breathing? Also, should I separate her from other chicks in brooder in case it is from something contagious? Anything I should be giving her or doing for her?
Also, the brooder isn't too hot and the chicks have plenty of room to get away from heat. No issues with the 8 other chicks. She doesn't seem to have any other symptoms that I can tell. She is a cochin bantam. She did gain .1 oz (.9-1.0 oz) since this morning, same as my other chicks, so assuming she is eating ok. I had to be gone most of the day and couldn't monitor that. Thanks for any help. Here is a video of her breathing and rattling sound.https://youtube.com/shorts/b839riRq19s?feature=share

 

[Chicalina]

If all the chicks hatched together and if it is something contagious then they've all got it anyway and there is no point separating, in my view. It would also cause great stress and distress to the sick chick.

It could be an irritant in the environment, like smoke, or dust for example. What bedding do you have for them?

Sometimes a weak chick can't fight off something stronger chicks can. I'd put them all on vitamin water to give them a boost and feed some scrambled eggs with garlic in once a day.

 

[Blessedmamaof3]

If all the chicks hatched together and if it is something contagious then they've all got it anyway and there is no point separating, in my view. It would also cause great stress and distress to the sick chick.

It could be an irritant in the environment, like smoke, or dust for example. What bedding do you have for them?

Sometimes a weak chick can't fight off something stronger chicks can. I'd put them all on vitamin water to give them a boost and feed some scrambled eggs with garlic in once a day.

I only got 2 chicks from that lady. The other one from her is a week older and was in a brooder out in a shed so no one was hatched with her and have only been exposed to her for the last 2 days. I have larger pine shavings covered with paper towels so I can more easily moniter their poops. The other week older chick that I got from the lady had a couple poops with red on them when I first got it home. I first thought maybe coccidiosis so started them all on corrid. Now I'm wondering if it was just intestinal lining because no other symptoms? They are getting corrid water just in case.