Just as Mike says, these are the prices that fanciers are willing to pay when birds of this class go under the hammer.
Not forgetting that there were quite a few birds that sold for between £150 - £350, direct from top class stock.
I myself was fortunate enough to make a purchase which was well within my budget, but you can see how easy it is for fanciers to get caught up in the action as soon as the adrenaline gets going.
Roundo.