One thing with picking up back feet?
Do not V your hand and pick foot up with your thumb on one side/fingers on other, as you do with front feet. That can, if horse decides to kick, dislocate/break your thumb.
Horse's power in back feet is to kick backwards, front feet is to strike forwards, so the V works there, but to safely pick up back feet, cup your hand, keeping fingers and thumb together as you give cue to pick up foot.
Keeping shoulder against horse is good too, as it is anytime you are working around horse, or some part of you touching lightly as that will signal you if horse is fixing to move.
Horses make me a better person.