Really Sick Chicken that Sleeps all the time

Hi all.
We have a really sick 14 week old silver sussex that certainly has never been a straight forward chicken. Some of her symptoms and illnesses include:
-constantly sleeping (will only wake up if you tap her)
-when breathing, her neck bulges
-she has a snot like liquid coming out of her nostrils
-over the past few days she has stopped eating (we haven't seen her do it at all, even when the others are)
-she had a serious case of coccidiosis quite a while ago but we cured her and she hasn't been showing any of the symptoms associated with it eg. blood in poop
-sometimes she makes a clicking sound when she breathes
-she smells really bad (even though our other hens that live with her do not)
-she has crispy feathers on her wings that she has had since she got coccidiosis and they have not gone away

If anybody has any ideas as to how these could all be related and if their is anything we can do to save our girl could you please let us know. Also do you think we could be infecting our other 2 hens that she is living with that are the same age?

Thanks in advance

I would imagine she has a respiratory infection. I'd start there - maybe try treating with Terramycin, Duramycin, or Tylan. How long has she been sick? I'd keep an eye on her flock mates - consider quarantining her.

Thankyou so much for your quick response. She has been sick for a few weeks, although she has been getting considerably worse over the past few days/week. I think she may be depressed as we had to get rid of our rooster a few weeks ago, of whom she was quite good friends with.

We have been keeping an eye on the other hens, but they seem to be all good. I will look into getting some of that medication for.

Once again thankyou so much.

Tractor Supply or your local equivalent should have them. I'd probably go with the Tylan50 if she's been sick a while as it's a little more potent. You'll likely have to administer it to her via a syringe.

A few threads that may help you as far as dosage, administering, etc

https://www.backyardchickens.com/t/668686/tylan-50-dose

https://www.backyardchickens.com/t/216363/how-many-cc-of-tylan-50-do-chickens-get-help-asap/10

https://www.backyardchickens.com/t/589410/tylan-50-injectable-taken-orally

https://www.backyardchickens.com/t/378414/tylan-50