I knew of someone who did this years ago with mounted Canada geese. He had mounted them specifically for the purpose of using them as decoys, had sprayed some kind of protectant over them to keep them from getting damaged by the wind, and only used them in dry conditions/on land. He was also EXTREMELY careful with them.

Even then, they lasted less than one season. And the results were negligible because they didn't seem to bring in any more geese than any other decoy spread.

Think about it: if this was such a great idea, don't you think a lot more hunters would be doing it? I admire your zeal, but I think you'll be putting out way too much work for the payback you'll get in return.