I don't believe that to be credible in itself, but we could use John Law's schemes. There clearly was a tulip mania, though it probably didn't collapse the Dutch economy. The Mississippi scam or South Seas investment bubble OTOH wrecked French government and investors a like. Emus and ostriches did not collapse the farm economy but I know it bankrupted one person. Appraised the place. Her birds were all over the neighborhood and cops were hunting for her. Finally locals began shooting them and last of them were rounded up by a local exotic animal farm and dumped on their farm. Eventually they had to post a guard at the exotic animal farm to keep people from dumping unwanted birds on them, especially emus (ostriches were worth a few dollars but emus wouldn't sell with a $50 bill tied to their neck). I had one dumped on my farm once. Goofy and you can't herd them. Emu burgers are supposedly good, the oil is very penetrating and used to make arthritic creams. The processing house in Grove, OK has shut down and you rarely see them now.