I didn't think BBTS would be stocking them, because like Kreo this year, the Angry Birds were supposed to be a ToysRUs exclusive. Unless the ones they are listing are general release, and all the rest are TRU exclusives.
Considering their prices are about the same US retail, they must be getting them from Hasbro... who wouldn't sell them to other stores if they were meant to be exclusive.

But yes it sucks, as it's like Botshots, in which you often had to import the whole wave just to get a certain character, or buy a multi-pack... because there is just not enough demand for them to sell individual toys without the risk of being stuck with heaps of the lesser known characters.