You need to understand how the leucisitc gene works.
It is not actually a colour, it is a pattern where the pigments produces are restricted to the head and spine.
As such they can and still do produce a certain amount of xanthaphores (yellow/orange pigment).
Sometimes the leucisitc gene doesn't work properly, allowing pigment in places you wouldn't normally see it - like with piebalds. And this can apply to xanthaphores too, hence the all-over yellowish colour.
But once you add in the GFP gene (green fluorescent protein) that gives a general all-over yellow-green hue you get axies like the one in your picture.
And add to that the fact that some pellets, such as those with astaxanthin, can cause build up of pigment in the axies skin as well and you can get a range of colours!