Ok so I have no clue what happened or what to do for the other chicks.
They are polish. I have had them for a week. They are in with my silkie who is now being removed for fear he/she caused this. No pasty butt but some did have the starts of dirty butts when I got them. Their vents look good now.
There has been no sneezing, no off behavior other than they sleep weird, everyone was very vigorous with eating and drinking, the poop all looks fine. There were only 6 of them so its easy to keep an eye out for this stuff. no drainage
When I found it, it was laying on the ground and another chick was on it, It was gasping and its head was flailing all over, it had no control over its legs or body anymore it seemed. Its head just kept jerking like it was trying to lay its head on its back. Just kept stretching its neck way back over and over and gasping.
Last night it was still eating and picking on the other birds. They were all active enough last night I had to put a pillow over my head to block out all the noise.
So what could have caused this and whats my next step to protect the rest.