There are two different kinds of down sleeping bag. You can either get a goose fill down sleeping bag, which is made of goose down or goose feathers, or, a duck down sleeping bag.
Normally, duck down sleeping bags are typically a little bit cheaper and they are gonna have a lower fill power than goose down sleeping bag, which has a higher fill power and of course, a little bit more expensive.
Speaking of fill power, you must be thinking of “What is fill power?”
I work for 4Monster outdoor brand and before we have down sleeping bags on our product list, I had no idea about any knowledge of “fill power”. After we decided to bring sleeping bags in our brand, I did some study and I think it’s quite helpful for people to choose the right sleeping bag after knowing what is the fill power and what is the difference between the different fill sleeping bag
“Fill power” is a measurement that was created in mid-late period. It is used to determine the loft of down. And “loft”is the amount of puff that the actual down feather has.
For instance, if a sleeping bag is 700 fill power, then it has 700 cubic inches of loft. With 550 fill power only creates 550 cubic inches of fill. So you need more 550 fill in a sleeping bag to create the same warmth as 700 fill on sleeping bag because it fills less space. So typically a 550 fill sleeping bag is going to be heavier because they need more feathers to fill that area than a 700 fill sleeping bag!
So, it is not to choose a sleeping bag easily just by the kind of down, but also the fill power is very important.