Given the sofek, and considering that saying Thanks to Creator is a mitzva meduaraita, I hereby Proclaim that one should eat turkey without shehiyanu. Those who are extra careful about hashash avoda zara can eat b’shinui – either chicken, or using traditional Yidishe potatoes.
As Syag mention, in Golus we may do bracha of kiddush on the second day of Thanksgiving.