The Developer Birds were created exclusively for an advertisement for the Google Chrome browser. They are designed after and voiced by the original creators of the game: Peter Vesterbacka (CMO of Rovio), Jaakko Iisalo (Senior Game Designer of Angry Birds) and Serdar Soganci (Web Games Manager). The film lists their names as "Serdar, Jaakko, Peter - Angry Birds Developers.
The Developer Birds are not playable and have not appeared in any Angry Birds game or any other instance beyond this film. They were birds that display the ability to speak.
Developer Birds and their real-life counterparts
Presentations used in Video
The growth of AB Fans.
Why the birds are angry.
Foreman Pig got spoofed into the Bird Anger chart because of the green colour. In the games, Foreman Pig isn't shaped like that.