easiest and least stress on machine option is build a stone boat. its just a wood platform with a metal plate on the front to hook to and act like a ski to keep the front edge from digging in. then you can roll on almost as big of rock as you can imagine,
and hook it to the 3 pt and away ya go.
i have moved a few rocks so big my gradall couldnt lift them, and that has just over 8000lbs lift at the bucket. i rolled them onto the stone boat with our IH td9b dozer and dragged them away. if your cheap and frugal an old car hood makes a dandy stone boat! i have a hood from a wrecked 95 ford pickup that i use