I dont know if this will help, but after 15 years of use, I can definately say that for the $$ they are a great investment. Our biggest problem is lack of wind at times and of course rain. With no wind or during rain, what you have is a great big flock of nothing. We have used from as little as 2 dozen to as many as 1500. We have set out pods as far as 250 yards from main bunch to mimic what we see. We also not only tie,staple or tape the top ,we will also staple the underbelly several times to provide more shape.