Tug Kenny,
Here in France (where hunting is very, very popular) you can buy all kinds of decoys, life size ducks, pigeons etc. The largest I have seen is a Canada Goose. Some of them seem a little flimsy and would need bracing. They appear to be made of a rubbery, plastic stuff (hope that's not too technical for some of you chaps!).
Try the Internet for suppliers of hunting equipment.
If you want me to find out sizes and prices I could possibly buy you one and send it as they cannot be heavy.
Roger in France.