I believe that management of the prairie chicken is more or less up to the states in the US. Here in MN, there is a limited hunting season on them (greater prairie chickens). There is a population estimated at around 1100-2000 in MN. 182 permits are issued and roughly 100 birds have been harvested per year since 2003. The feathers are very close to a female ringneck pheasant and also a sharptail grouse which should be relatively easy to obtain. I have never seen a skin offered commercially but I believe there are also limited hunting seasons on them in the Dakotas and Mo. If you could find someone who had a permit, you might ask them to save you some feathers. I actually have skins from ruffed, sharptail, blue and English red grouse and they are all wonderful fly tying materials. I would like to add a sage or a spruce to the collection but I have never seen them offered anywhere even though they are hunted in various states in the US. The MN DNR says that 10-20 thousand spruce grouse are taken each year in MN but none of my many friends who hunt grouse here have ever taken one (at least not when I ask).