all, This morning when I went outside to open up the dorris for the chickens, I noticed one of the hens doing this (see you tube link). She was perched when I closed them up last night...the poo on her neck suggests she fell last night and started the convulsions? I have quarantined her. What could this be? She won't stop, though she did temporarily when I picked her up. She lifted her head and looked at me.