Several factors determine the quality of down.
The bigger the goose, the better the down: European goose is larger than Asian goose, so the down is better. The colder the place, the better the down: the down quality is best in the cold regions of the Arctic Circle.
The longer the feeding time, the better the down: free-range goose and duck have less down smell and better fluffy.
But now it is more hormonal feeding, with short feeding time, heavy smell, small velvet, high oil content, and poor resilience. This is why some duvets seem to be cheap, but their warmth retention has been greatly reduced.