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 lisalo (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 the only birds to display the ability to speak, until The Angry Birds Movie was released. The film can be seen on YouTube.com, posted by Google Chrome's official channel here: