Casting the Hex spell initially requires a verbal, somatic, and material component. For the duration (concentration up to 1, 8, or 24 hours depending on spell level), if something dies while hexed, I can use a bonus action to apply it to a different creature.
Does reapplying Hex to a new target (after the previous one is reduced to 0 HP) have a verbal, somatic, or material component?
I am wondering whether or not it would be obvious that I was reapplying the spell to another target or if I would have to try and hide it. I could, in theory, kill something I've hexed and then several hours later sneakily apply the spell's disadvantage on an ability check to a creature and he would never know (or his friends would never know).