Important Things to Consider
Having a bird like a Heath Hen is a very exciting deal and piece of early American history. The main things for this particular bird when it comes to price/selling is that he is the most difficult. With a passenger pigeon, labrador duck, carolina parakeet, you can look at them and right off the bat know what they are. The Heath hen being so close to the greater prairie chicken is such a tough situation because the only way to really know for 100% is to have a DNA analysis.
The normal process I try to mention to potential sellers for a bird like this to get the very maximum in selling price is to run a DNA analysis which a professor that I believe now at the university of Texas does but very expensive (1,000-2,000 range) and takes a while to obtain. I've tried to get the DNA test most people hear about in ads and contacted about a dozen different one's for my Heath Hen but they do not do the same test as to determine birds in the subspecies sense.
A musuem curator or ornithologist to verify is always a plus but for them very risky because without collection place,date, DNA it can only be a guess and if the bird is say bought for a certain sum and they at some point do get DNA done but comes back a greater it would fall directly upon the person who "verified" it. The one's I have spoken with in the past have always avoided that with me from reasons of "saying it's a Heath Hen would assignvalue and that's against our policy" (Smithsonian curator's words) to another that said "Without a collection date, location, accompanied by DNA there would be no way to call a bird a Heath Hen" (University of Michigan professor). At the same time cannot blame them because of the implications that would ensue if not in fact a Heath Hen.
For what I can share as to value I know of only one that has been sold and that is the one I bought. I paid right under $1,000 dollars and overall a pretty nice bird,case,etc. I have seen victorian era prairie chickens for sale on occasion in Europe that are in the maybe Heath maybe greater and the last sold (along with a ruffed grouse in a pretty big case) for $600 US dollars. The one prior wasn't in the best shape and didn't end up selling. Hopefully these figures will help as it's not something that comes about everyday and no set standard when it comes to value because of the nature of the item. It's something I check for daily on the US and UK ebay along with nationwide craigslist, large natural history auctions, etc.
The backstory on mine is he was on eBay and the bidding got towards the 600-700 range then the seller was asked "well how do you know it is a Heath Hen and not a greater" which is certain to be the first question asked to anyone selling one. The seller's response was that the bird can be DNA tested and if not then returned for a refund. Of course nowadays most think of the test as the $29.99 anywhere test but come to find out the hard way that 99% of those are just for paternity. So the bird ended up getting kicked off eBay and I had her information from prior discussion and worked a deal with her off eBay and bought it. The professor was intially at the University of Michigan and did a huge study involving a special DNA sequencing where he tested museum Heath hens, greaters, lesser's, Attwaters.
So overall while most think extinct anything and the dollars signs go off it is not the case with this particuar bird I'm sad to say. If going into the situation with DNA confirmation, verified by a curator, or to have exact speciment date/location data from where it was taken. There leaves a very large gap in maybe's and uncertainty which some very interested buyers may overlook but if said bird comes back 5 years later after a DNA was ran that says it is a greater there will be a lot of money to have to return.