I wouldn't say there rare. Out of a group of 6 juveniles I started with 3 turned out white. I've traded thouse and now trying to breed stronger orange colours. Me personally are not to keen on plane white, I prefer orange/red.
I hand picked my 6 and chose ones starting to peel at 1.5 inch. Now if I could turn back the clock I would of chosen one that were showing no sign of peeling. I found the later peelers turned out to have more colour. Well in my case anyway.
Also ones with little colour pigment sometimes end up blind.