Help needed with a chick in quarantine

[Nksg75]

I need some advice on a 8 week old chick I have had in quarantine for 2 weeks.
I decided to add 2 Black copper Marans to my other 15 week old silkie and EE flock.
I wanted to add before all were grown and thought it would be easier to add now instead of when they were older. I found a man on Craigslist who hatches chicks and talked to him extensively, about this.
I hatched my own chicks, however always wanted some dark brown eggs eventually, yet never had any luck hatching those BCM eggs.
So 2 weeks ago I went and bought 2 of his BCM chicks that are somewhere between 8-9 weeks old.
Needless to say, the brooder was overcrowded, and they didn't have much human interaction before we got them. They seemed very frightened of us for days and days. I finally got them eating out of my hand, after 2 weeks, however 1 chick constantly sneezes. She has since the day I picked her up in the car ride home. Of course I looked her over before picking her, yet as would be the case she started sneezing halfway home!!
Anyway since it seemed they were overcrowded and the poop seemed a bit odd, I asked on the forum about it, and it was sugessted I put them both on corid.
They were on it for about 5 days and the poop seems back to a normal color. However this chick is sneezing since that first day. No other signs of illness, she eats fine drinks fine, seems healthy otherwise, yet even though I have put her on staight newspaper and paper towels to be certain it was not the dust factor she still is sneezing.
I was wanting to introduce them to my other chicks soon, as I am on a time schedule to get them all out to the coop at our farm by spring break, I am concerned about this one chick getting the others ill.
What in the world could this be?
I have looked over different illnesses, and I am just stumped about this one chick.
What would cause this yet show no signs otherwise?
After 2 weeks I thought something would come about if she did indeed have a illness, yet the whole time the other BCM chick in quarantine with her is fine.
Sorry about the lengthy post, I just am worried about my other chicks I have babied since they hatched.
BTW no one has had any vaccines, and I have the fowl pox vaccine waiting to give them all at the same time before placing them in our coop.
(South Texas has horrible mosquitos and last summer I had a flock who had fowl pox.( I don't have them anymore)
Thanks in advance for help.

 

[Pork Pie]

Guess the sneezing could be caused by a range of things, from something fungal, an allergy, bacteria or virus. Your other birds may not be showing symptoms because they have some level of immunity to whatever the problem is, or if it is an allergy, then they would not be affected.

Decision, decisions... Personally, i would simply cull both birds as introducing what could be a viral respiratory infection to your whole flock for the sake of two birds is not a risk i would take.

All the best
CT

 

[Breakofday316]

I would definitely wait on introduction. I had multiple chicks, around 6 weeks old have the same issue. Just sneezing all the time. They ate well, pooped well, ran around just fine with the flock.As the weeks passed more symptoms became present: shaking head, appetite slowly declined, never started laying eggs at appropriate time, then things just continued to go down hill as time past. Over month and months, the chickens symptoms got worse. Leading to inability to walk, stand, and uncoordinated behavior. Then death followed.

I am not saying this is what your chick has, however just warning you that I introduced new chicks to my flock of 7 hens too soon and now im down to just 2 hens. I would watch that chick for some more time to see if anything else arises.

Hoping it all is just ok.