thin, like maybe the boats, but here's how Grayson Chesser "antiques" stuff like decoys....
Apply dents as required....
Paint it with oil paints....heavy...then set it on fire while the decoy is still wet....the solvents in the paint will burn off without damaging the decoy, (assuming you control it).....before the flames go out on their own hit the bird with a spray bottle of water....small drops of water will make a little crater like depression....more water will cause the hot paint to crack.....
Let that cool and then take pumice, "rottenstone", and dust the decoy liberally to completely cover the decoy....using your hands, rub them through your hair first to pick up oil or if you are sweating wipe your forehead to pick up the oil from there, and the rub the rottenstone into the decoy.
Eventually it will either be all rubbed into the decoy or will fall to the floor....what you'll have left is a decoy that looks like its seen honest use in the marsh for years....the rottenstone will dull the paint and lightly scratch it in a random pattern....all of the little cracks and crevices will be filed with it and that will provide all manner of different effects from heavy dark cracks to light ones...
Little boat model might be too fragile to set afire but a raw umber wash, wiped off immediately after application and then the same application of rottenstone as above will "age" those without fear of watching your handiwork go up in flames....
Shoot me your e-mail address and I'll send you some pictures of a heron decoy being burned and what it looks like afterwards..
Steve
