It's possible that they are escaped domestic turkeys, but I am pretty sure they're wild. Most of the apparent mass you see on any bird is plumage; they can look significantly fatter or thinner depending on how fluffed up they are. The males only fan their tails like that when displaying. Normally, their tails are folded up unremarkably behind them. Also, I think your female might be a yearling male (also known as a "jake"), since female turkeys usually have feathers most of the way up their neck (http://en.wikipedia.org/wiki/File:Female_wild_turkeys.jpg).