An update
After another big dip she finally seems to be recovering.
She is outside again, with her friend Heidi, she is even eating something out of her own movement, but I am still feeding her 2 times a day.
The main reason for my update is following: She broke down after going upward (18 of may) because of a nasty bacteria in her krob? Crob? The bacteria produces a 'chemical' which causes neurological problems.
So the eye, the head twisting and not being able to walk, the stomach trouble and horrible bacteria infested poop was probably caused by this bacteria.
One of the characteristics of this kind of infection is that the food doesn't pass the crob anymore: it stays full. Even water doesn't pass.
We were checking her crob and thinking she was doing well, but in 1 to 2 days she went downhill and nearly died.
Because the outside problems, with the inside cause don't relate naturally/logically I thought it might be interesting for someone with a chook with similar problems.