I'm mounting a sage grouse in a booming pose. I have read past threads that advise against trying this with a fall bird, but the customer insists on it. I was wondering if there are any manufactured air sacks for a sage grouse? I've done some looking and haven't found any. If there aren't any on the market, I'd appreciate any info on how to make your own. This will be the second sage grouse I've mounted...the first one was abysmal. This bird is much more mature and in better condition, so I'm hoping with some advice I can improve on the last one.