Hi smmimp14,
A down/feather topper or featherbed or a fiberbed is more “fluffy” than resilient and while it can provide some degree of localized pressure relief under pressure points … it is much less resilient than a foam topper and won’t redistribute your body weight as effectively or provide the same degree of pressure relief as a foam topper. It will also pack down and compress more, requires more maintenance and regular “fluffing”, and with your weight it also won’t be as durable as a good quality foam topper. There is a little more information about featherbeds and “down alternative” fiberbeds in post #10 here and in post #6 here and in this topic about featherbeds.
There is also more about the different types of softness in post #15 here but a featherbed or fiberbed is more of a “feel” product than a “pressure relief” product and unless you are just looking for a little localized pressure relief under pressure points or a different “feel” for your sleeping system they probably wouldn’t be your best choice.
Post #2 here and the topper guidelines and other posts it links to also have some suggestions about choosing a topper that may be helpful.
If you do decide to try a featherbed anyway then post #2 here and post #10 here has some sources for featherbeds that also have some good information on their site. Fiberbeds filled with polyester are widely available at some of the big box stores or on Amazon and other sources that have a good return policy so with their lower cost and good return policy there would be little risk in trying them so you can decide whether they are suitable for what you are looking for based on your own personal experience but I also wouldn’t expect any of these to last very long either.
Phoenix