No way will he need a pony size, at least cob if not full. I have a full size webbing harness that fits 14-14'2 Highlands so it depends how big he matures but the finer head might need a cob size bridle and the bigger back end a full size harness. You don't always get the bridle with the harness anyway so worth an investment if something you like has come up affordably. They don't lose value. And if he grows through the cob size to require full at maturity, at least you'll have had it in use for a year or so on the way.
As an aside, can anyone tell me what a full size webbing one costs second hand these days? I don't suppose I'll be driving again so it might be time to put it on ebay, just not sure where to start with pricing. Thanks and sorry to divert the thread
