Ivory is a super YB and not a true lucy I believe since it retains some color/markings


(img from WoBP)

You can get lucys from several different crosses, they're usually the super form of other co-dom genes; mojave, lesser, fire and phantom. The super forms of these snakes will either produce Black Eyed Leucistic or Blue Eyed Leucistic snakes, known collectively as the BEL complex genes.

I'm not sure what you mean by ultra, unless you're talking about ultramelanistic, which is a totally different thing.



As to the health of the snakes, I have not heard about anything specific to the BEL complex health wise, but I'll let someone with more experience in that area answer.