Im dealing with Marek too, and my two sick birds look like yours. In Marek the pupildexolours (becomes paler instead of the strong orange-red), each pupil can have a different size, bird looks droopy and weak, quickly becomes emaciated, seems not to pass food properly (I have sometimes mistaken...
Years late but I can clarify. There are 3 reasons for "wry neck:
1) vit E deficiency
2) vit B deficiency
3( cervical sciñoliosis (bone malformation
The first two can appear just as they hatch, but might develop later. They are easy to treat, but as it's difficult to tell which vitamin is...