I am having a similar problem...
My chicks are 5 weeks old, they are outside, but with two heat lights in a draft free area broody area they can come and go from. They have been outside for over a week and at first they were all lively and running all around...now, a second chick is standing in the broody area, head sagging down and wings drooping to it's side. It won't lay down, even when other chicks come lay down next to it...just stands there, head hanging down & wings drooping.
This is the second chick with the exact same symptoms. The first was two days ago.
Their area has brand new pine shavings. they have three waterers with vitamins & electrolites and they are on medicated chick feed.
I have looked up every single chick illness and none match. They don't have dark faces, they aren't breathing oddly...just extreme droopiness.
Anyone have any ideas??????