Part of owning animals is knowing when to make a judgement call like that, experience will help a lot with that sort of decision.
Yes, to clipping the ducks wings, or rather just the one wing, just the main flight feathers, if you google or youtube it I'm sure there will be examples of where to cut.
Why is your ram wearing a raddle? Once he's done his job and the ewes are marked I can't see why you'd want to keep it on - maybe change the colour of the crayon if you want to know if any of the ewes didn't take first time and came back into season?