Is she laying any eggs?
Can you post some photos of her?
Green poo in your case, since she is not eating can be an indication of not eating enough.
Has she been wormed?
It's possible that she may have an internal laying problem such as Peritonitis.
As suggested above, give her some nutri-drench or vitamin water you can also wet her crumbles to encourage her to eat. If she won't eat her normal food, then you can offer some hardboiled egg or tuna.