So I have a 4 year old black rock hen who has always been an "odd one" her toes are all bent and not straight and she does this weird thing where she jurks and moves her neck suddenly- it's really weird. But the main thing is she has a massive crop (about the size of a large tennis ball) also her feathers haven't grown over it so it is bald and you can see the skin. It wobbles when she walks. The weird thing is that she doesn't eat an unusual amount and no more than my other normal sized hens! If anything she eats less than them because she gets pushed around by them and is near the bottom of the pecking order. What could this be? What can I do to help her? Is this serious?