There are different species of peacock Definately pays to do your homework on different ones available before you buy and make sure you buy from breeders that keep nice clean lines (Don't buy from a mixed peacock tank!) :-?
And when buying from a store, it is always good buying from a store who is good at keeping species seperate, some are good, some not so good. I order in mine and pick them up still in their bags, straight from supplier, even tho the shop I go through is great with keeping peacocks etc seperate