The reason I prefer to tie the hackle at the head and wind it toward the tail is because you get a nice tapered shape to the hackle. Also, if you tie the hackle in at the tail and, as you wind it forward, it happens to break, you're SOL. You now have to undo the body, tie in another hackle, redo the body and then wind the hackle(again). Plus it's difficult to get the nice tapered body. Just sayin.