boom

noun, a moveable arm used for lifting, maneuvering, etc. (COD,1)

“…have a big tree that you used to hook up the horse-fork rope to-”
“The boom.”
“Yeah, boom or something, and with the horse fork you just drive it into the hay and then it has things on the bottom that turn to hold it, and then you bring it up. You had to have a pulley up high somewhere; usually it was in the mow…”

“Yeah it was on the boom, and then the boom would swing, so then it would swing. You’d pull it back over to the wagon and then you’d stick it, and then it would go up, and then the boom would swing back over where the [hay] stack was, and then you’d drop it.”

“Tom used to put me on the skaffell on the side. I didn’t know how to pitch hay. I sure learnt. Somebody’d pitch it up to the scaffle, and then I’d pitch it from the skaffell up to the top of the stack, and I couldn’t build a stack to save my life, have it all off to the side, and probably then it ‘d eventually fall over.”
“Used to have it under a tree?”
“Sometimes we did, other times we’d just use the skaffell. We really didn’t have any trees right close by to put the boom, whatever you call it.”