I have been hatching a breed known for its hatch issues so much so that hatcheries tried and stopped attempting to incubate them so I have dealt with many assisted hatches. Every single one either immediately or within days of hatching displayed a vitamin deficiency. Every single one also grew at a slower pace and feathered in slower compared to the others. Once they reached maturity you would never know. I dose them daily for 1 week with Poultry Cell and then once a week for the next 2-3 months after that to assist with growing. You may have to dose with more vitamin E for the wry neck. Poultry Cell has both vitamin e and selenium so I have also used it to treat wry neck, but if the deficiency is severe enough sometimes they need more vitamin E. As for the eye do they have water deep enough to fully dunk their head in?