Thanks everybody. Sadly, we lost the girl last night despite our best efforts. She was a sweet girl and will be missed. I haven't seen anyone else in the flock with similar symptoms, but will definitely be on high alert.
Our eight month old Ameracauna hen has started making a strange motion with her mouth. My initial thought was a respiratory infection and treated with Tylan. When that didn't work I tried de-worming (flock was due anyway) with Rooster Booster Multi Wormer. Still, no improvement. She does...