Even though both are used in the production of down vests, goose and duck down do not offer the same level of quality. In general, goose down is better than the down sourced from a duck, and there are a few reasons for this. When talking about how lofty down is, you need to mention down clusters (collections of fine down feathers). The larger a cluster is, the better it works as an insulator.
Because geese are larger birds than ducks, these clusters are usually larger too. In addition, they are most often harvested from older birds (as a byproduct in other industries), meaning that these birds got the chance to mature and the down has developed properly. All this leads to high-quality down with excellent fill rating.
Duck down, on the other hand, comes in smaller clusters. Ducks are smaller birds and their down isn’t as efficient insulator when compared to goose down. An additional problem is the odor – while goose down can be almost odorless, duck down can have a strong odor. This means that it needs to go through more intense treatment before it can be used.
However, all this doesn’t mean that duck down is bad. Its main advantage is certainly affordability – it’s more widely available and much cheaper to produce. Manufacturers use it in their products because it allows them to lower the price and make the vest affordable to a larger number of people. However, the best winter vests use goose down with high fill ratings.
But when talking about vest performance, we shouldn’t limit ourselves only on the down source. As we discussed earlier, the fill power and weight also play significant roles. While goose down is usually better rated, a 700-fill duck down is still going to outperform 600-fill goose down. Also, don’t forget to consider the amount of down used.