I know my girls would twitch there heads if it gets to most in the coop. I just open a window and the twitching goes away? Dont know if thats what's wrong with you girls? But it helps my girls. Good Luck!
I knowest, my girls would do that if! There is not enough venting (open windows / reduces moister in the air) look at your girls. do their feathers look wet or kind of damp? I open there windows and it stop. don't kown if that what's wrong with your girls but it helps my girls. Good Luck