Angry Birds (video game) featured app on the UK App Store in February 2010 and quickly reached No.1 there, it reached the No. 1 spot on the paid apps chart in the US App Store in the middle of 2010 and then stayed there for 275 days. The initial cost to develop "Angry Birds" was estimated to exceed €100,000, not including costs for the subsequent updates. For the iOS version, Rovio partnered with distributor Chillingo to publish the game to the App Store. Chillingo claimed to have participated in final game polishing, such as adding visible trajectory lines, pinch to zoom, pigs' grunts, birds'
Angry Birds "Bad Piggies: Egg Recipes", along with doodle books based on some characters of the game. After a few weeks of the release of Angry Birds Space, they also released Angry Birds Space books about numbers, alphabets, and stickers. On 20 March 2012, "National Geographic" published a paperback book titled "Angry Birds Space: A Furious Flight Into The Final Frontier" shortly before the release of "Angry Birds Space" which became available on 22 March 2012. National Geographic also has a book titled "Angry Birds Feathered Fun" for learning all about birds. In the same year, Rovio created a contest with the