Noticed one of my 15 week old chicks do a weird sneeze/hiccup type thing yesterday, she was totally fine otherwise, eating, drinking, active and happy. But I just got home from work and checked on her, she seems lethargic, and is breathing through her beak probably half of the time... her sneeze things have also become much more intense... they're so forceful that they make her fall over every time. I haven't noticed any discharge from her nose or mouth... its come on very suddenly.... I have no idea what to do... I'll go and separate her from my 3 other chicks now... but has anyone seen these symptoms before or know what I could to to help her? I'm quite fond of her, and don't want to lose her.