You get a visual when a baby inherits a copy of the gene from both parents, and therefore HAS to have 2 copies of the gene to express albinism.
When you pair two albino's together, they both have 2 copies of the gene to contribute to the offspring, therefore all their babies will get 2 copies of the gene (one from each parent).
When you pair two hets together (a het has ONE copy of the gene and ONE copy of the wild type (or normal) gene), the babies can either inherit:
Normal gene + albino gene = het albino (normal appearing)
Normal gene + Normal gene = Normal
Albino gene + albino gene = albino.
So, that's 25% chance of albino, 25% chance of normal, and 50% chance of hets.
Out of a four egg clutch, statisically, 1 of those would be albino, 1 would be normal, and 2 would be het albino.
Of the three normal APPEARING babies, 66% of them (2 out of 3) have a chance to be hets. So each baby has a 66% chance of being het albino statistically. That's why het to het normal appearing babies are called 66% possible hets.