Dont know what year it was, I think around 1996/7, the temperature was minus 27 in Scotland.My loft was in the middle of a field and when I changed the frozen water in loft, the time i was ready to leave the water had frozen up again. I had birds sitting on small ybs, no nest felts, no electric and no heaters. Never lost a yb, in fact the down on ybs was fantastic. A brilliant team of ybs were bred, gaining top prizes every time they were raced.