It is possible. The most likely explanation is that the parents are evolved from an "albino siblings strain" In most peacock incidents is from a crossing of an albino species in the background, likely to create an albino German Red strain.
I just had the same thing happen with my pseudo. flamebacks. Out of 15, 2 were albino. I've had 3 generations of this strain and to my knowledge there were no ablinos ever in the lineage. So I was very surprised to get albinos. Talking with a friend, who is a biology major, he told me that it is possible for the fish to carry the albino gene through many generations before it will show up. So just consider it a bonus. :thumb:
Albinos occur in nature, but it is a recessive gene I believe. All that has to happen is that a couple of recessive genes make the cut and blammo, you've got an albino.
My friend's mom breeds cats, and one of her males must have an albino gene, because in a few litters of kittens from that cat, she gets an albino every once in a while.
If she took those albinos and bred them, she would have a much higher chance of breeding albinos as well.
Keep in mind, it's possible for albinos to breed regular offspring as well. I had a spawn of my albino red-top zebras, and out of 17 fry, 2 were not albinos. They were regular blue with a orange/yellow top fin and edge of their tail as they got older.