A little bit of background:
This is my first year ever raising chickens. We got 4 chicks this spring and raised them. They're all healthy and have just begun laying.
Last week, we decided to get two more chickens. (It was a bad idea and we're never buying grown chickens again.) They are molting. I put the new chickens in with our existing chickens the night we bought them (terrible mistake on my part.). After two days, our hens had pecked one of the new girls so badly that there was blood around her tail where the feathers haven't come in yet. I pulled both of the new hens out of the coop and put them in a dog crate in the garage after treating their wounds.
They've been in the garage for 4 days now, and their wounds are healing nicely.
Two days ago, I noticed that one of the hens started coughing after I put some food on the ground for them. I assumed she had swallowed a pine shaving along with her food and didn't think much of it. Yesterday, I noticed she was sneezing, wheezing, and coughing. But other than that, she was behaving, eating, and drinking as usual.
Today, she seems worse. There is a clear discharge around her eyes and beak, and she is still sneezing and wheezing (though that is better than it was yesterday).
I'm getting concerned about her. I gave her some yogurt yesterday, hoping that the probiotics would help her immune system, and it made her poo really runny. I gave our four other hens yogurt as well, and it had no affect on their poo.
What can I do for this sick girl? Is it possible that the stress of molting and being relocated is too much for her? Or am I dealing with something more serious?
Any ideas would be welcome!