One of mine was having the problem of hanging her head and stumbling. Took her to the vet next morning and he said vitamin deficiency.
He recommended MINIMUM 20% non-medicated chick starter (No where to get the ratite feed around here so have to order it), finely chopped veggies (carrots, kale, spinach, apples, and grapes) and fruits, and to add poultry vitamins to their feed or water (depends on which you get). After a vitamin shot and adding the vitamins, she's doing great. Still ordering the ratite starter feed though so they have what's needed, unless we find something comparable.