1.) What type of bird , age and weight (does the chicken seem or feel lighter or thinner than the others.)
Black Australorp, just over 1 year old, yes thinner and lighter
2) What is the behavior, exactly.
Lethargic, not eating although seems interested, takes one peck then...
https://m.facebook.com/video.php/?video_id=790882915802028
I have never heard my chickens make this noise before, I googled it and found it sounds like purring but it's lower pitched than the videos I've seen, she isn't lethargic or showing any other signs, she seems perfectly happy, she was...