I guess the question you need to ask yourself here is "are the feathers loosly packed? or compressed to the same density as the lead?" If they are loose, you could spread them out throughout the plane to evenly add a pound so there is not one single mass of weight to "unbalance" the planes' gyroscopic inertia which could cause unsightly or unpleasant flight characteristics. You could also use it to laterally balance or CG balance the airframe. You could compress it to the exact same density as a human body and use it as a crash test dummy in your airplane. You could use it to find the most desirable spot to "mount" your small pet in the airplane for a ride and still maintain good balance... as your pet lie zip-tied and taped to the inside of your canopy so the little guy can see how much fun he's about to have as you pull up for a verticle rolling takeoff. The possibilities are virtually limitless as to what one creative individual could do. I believe the answer you seek lies within the answer to another question... "What would be the feather-packing density?"

Brian

[8D]