Dying brahma chick; need help diagnosing what's wrong

[Thread-wing]

So I just got four new chicks a little under a week ago, and I'm housing them in a large plastic bin with sawdust bedding and a heat lamp. I don't know exactly how old they are, but they're just starting to get their first adult quills. The whole lot of them had a mild case of pasty butt, which I took care of a few days ago. I also noticed that my brahma had a strange habit of shuffling backwards a few steps before pooping, as though it was really difficult for her. I didn't think much of it until a couple days ago, when I noticed she appeared to have a swollen abdomen, like the left side looked larger than the right. However, it didn't feel abnormal, just that it was larger than normal, so I let it be. Yesterday I noticed she wasn't as active as the other three, and she'd stopped eating and drinking. Then this morning I noticed she was extremely lethargic and having difficulty keeping up with the others. Whatever is wrong is happening quickly, because now she's just huddled under the heat lamp, eyes closed, leaning back and breathing laboriously.

I just changed out the bedding and food/water, but I'm afraid there's nothing else I can do for her. What I really want to know is; What is she dying from? Is there a way to treat it? Will it affect my other chicks?

Thanks for your help, I'm trying to make her as comfortable as possible for now.

 

[Suzie]

A couple of thoughts to consider...

Firstly I would suspect wry neck...she may need extra vitamins...B and E..

Secondly..she may have signs of cocci...Amprolium in their drinking water is the treatment for this

 

[Thread-wing]

Update: I've removed her from the enclosure and put her in an open shoe box filled with sawdust. She's still alive, but will be leaving very soon.

My other chicks seem perfectly healthy, no lethargy or loss of appetite, no odd behaviour. The enclosure has been completely cleaned from top to bottom, and I still have no idea what caused this. My only guess is that she may have contracted something from my supplier, and I can only hope that she didn't spread it.

I'm trying to find someone to euthanize her for me, but I'm not having any luck, and I know I can't do it on my own. All I can do is try to make her as comfortable as I can