A molded decoy like yours and the damage you show could be fixed with a small amount of apoxie sculpt. You can get it on amazon and it wouldn't take a lot for just one decoy. It's a two part epoxy putty that sticks to just about anything and can be smoothed out with a little water and even sanded after it cures a day or so.
That old method of burlapping was likely a reasonable way to get a texture on the surface of the decoy, but it's also a way for wear to introduce water into the burlap and speed up the wear. My approach is quite a bit different, no burlap texture will show through what amounts to several thin coats of tile adhesive till the surface is smooth. Then a few coats of oil based enamel as a sealer, it soaks into the tile adhesive surface. At that point, I can either just paint it with oil based enamels or in my usual manner I like to strengthen it with a coating of flocking, then paint.
This past winter I had a friend send me a half dozen of several hundred decoys I've made for him that something had decided to kill. Why the unknown critter decided on just one bag of decoys out of dozens we will never know. Why mostly head shot kills on these six is still a mystery, but I'm thinking maybe a weasel or squirrels in the decoy shed. At any rate the repair was more extensive than what you are dealing with and since they are all flocked it added some more finishing issues.
I don't want to add weight to the repair, so I leveled out the holes with gorilla glue and scraps of foam that I used to carve these types of foamers.
Once that surface is smoothed I added a thin layer of apoxie sculpt to blend it back into the burlapped decoy's head and sand it smooth.
The color is kind of off in this picture, I have a new camera now, but these are the rehabbed decoys after flocking and paint. In order to get a good blend between the patches and the original head, I flocked the patched, then sanded the whole head to even up the surface, flocked the head again so it would be uniform and painted with oil based enamels to finish it off. The only other extensive repair I've done on this type of decoy was a couple that a retriever decided to take a bug chunk out of, it looked like a shark attack, it was repaired the same way.
