Hi....I am a new member. I recently noticed one of my barred rock chickens had a hard time walking...she would fall over. She was stumbling all over and unable to balance. She was still able to get around and I thought maybe she had a hurt leg that would heal but today I found her dead in the coop! Did she have some sort of disease? I'm worried my other hens will get it...please help! Thanks! Bethany H.