Sick Chicken

[chickedy chick]

I have a chicken that wont eat, has weight loss, puffed up, darkening comb and has diahorrea. all my other chickens seem fine. have given wormer. she is drinking plenty. Can anyone advise please

 

[mmajw]

How old?
What Breed?
What food?
What bedding?
Any contact with anything like mice/rats or their feces.?