The Tab has an article on what goes into the creation of down puffer jackets, and down products in general:
Feathers from live birds are considered more valuable to the feather industry, meaning the majority of birds are “live-plucked” 3-4 times a year.
If you want to see how this is done, watch this:
There are plenty of affordable, and usually cheaper, down alternatives on the market. There’s zero need for this type of abuse!