Pig Days

Pig Days was a special advent calendar for Angry Birds Seasons released on July 3, 2014 (along with the update of South Hamerica).

Appearance
It appeared on the South Hamerica Update. It only appears when you select the Play Button. It can also appear if you're on Season 2010-2011, Season 2012, Season 2013, Season 2014, and Season 2015. It has ended in Summer Camp update and replaced with The Pig Challenge.

Gameplay
From July 19, levels are unlocked from every specific day, and has each level with a different festive day. The first chapter has 15 levels and the second has 9 levels.

Side note
There is a list of holidays celebrated and the dates they were established. In the case of historical events, the year of the event is stated. Not all historical dates are correct, they have been taken from multiple sources.

Chapter 1: v4.1.0

 * Sun. 20 July 2014: 45th Anniversary of the Apollo 11 moon landing (1969)
 * Thu. 24 July: Opening of the San Diego International Comic-Con Convention
 * Mon. 28 July: 4th Anniversary of the creation of Angry Birds Nest (2010)
 * Sat. 09 August: 841st Anniversary of the groundbreaking of the Leaning Tower of Pisa (1173)
 * Wed. 13 August: International Left-Handers Day (1976)
 * Tue. 19 August: National Aviation Day (1939)
 * Sat. 30 August: Bacon Day (2004)
 * Sat. 06 September: NBA Finals (2014)
 * Tue. 09 September: Moon Festival (Shang dynasty, 1600–1046 BCE)
 * Fri. 12 September: Video Game Day (?) 
 * Fri. 19 September: Talk Like a Pirate Day (1995) 
 * Mon. 22 September: Hobbit Day (1978)
 * Mon. 29 September: International Coffee Day (20th century)
 * Fri. 10 October: World Egg Day (1996)
 * Mon. 13 October: Columbus Day (1492)

Chapter 2: v4.2.0

 * Wed. 15 October: Learn to Code Day (2012)
 * Fri. 31 October: All Hallows' Eve, or Halloween (1556-1745)
 * Sat. 1 November: All Hallows' Day (circa 5th century AD) 
 * Sun. 2 November: Day of the Dead/Dia de Muertos (circa 1000 BC)
 * Wed. 5 November: Guy Fawkes Night (1605)
 * Tue. 11 November: Ahtisaari Days (unknown, commemorates President Martii Ahtisaari)
 * Tue. 18 November: William Tell Day (1307)
 * Fri. 21 November: World Hot Air Balloon Day (2004)
 * Thu. 27 November: Thanksgiving (1620s-1630s)
 * Thu. 11 December: Bird-day (5th Anniversary of Angry Birds) (2009)
 * Wed. 31 December 2014: New Year's Eve (2015)
 * Fri. 2 January 2015: Sci-Fi Day (1920)
 * Tue. 13 January: Rubber Duck Day (1970)
 * Mon. 19 January: Popcorn Day (?)
 * Wed. 28 January: Data Privacy Day (2007)
 * Tue. 3 February: Windmill Day (?)

Chapter 3: v5.0.0
* This was not the date of the start of the California Gold Rush. That was the date gold was first found in California, in 1842. Infact, the gold rush started in 1848 - i.e. six years later.
 * Sat. 14 February: Valentine's Day (269)
 * Mon. 16 February: Opening of the 2015 Rio Open (2015)
 * Thu. 19 February: Chinese New Year, Year of the Goat (?)
 * Fri. 27 February: Polar Bear Day (?)
 * Tue. 3 March: Centennial of NASA (1915)
 * Mon. 9 March: Anniversary of the California Gold Rush*
 * Tue. 17 March: Submarine Day (1898)
 * Fri. 27 March: Hanami (Cherry Blossom festival) (Nara period 710-794)
 * Fri. 3 April: Easter (30 A.D.)
 * Sun. 12 April: Yuri's Night (first flight into space) (1961)
 * Wed. 22 April: Earth Day (1970)

Chapter 3 (cont.): v5.0.1

 * Fri. 1 May: May Day (?)
 * Tue. 5 May: Cinco de Mayo (1862)
 * Wed. 13 May: Leprechaun Day (?)
 * Fri. 22 May: World Goth Day (2009)
 * Fri. 29 May: End of the Middle Ages (15th century)
 * Thu. 8 June: World Ocean Day (1992)
 * Fri. 12 June: World Magic Day (1927
 * Fri. 19 June: Midsummer's Eve (1st century)
 * Thu. 2 July: UFO Day (1947)
 * Tue. 14 July: Pandemonium Day (?)

Chapter 4: v5.0.1

 * Mon. 20 July: 1st Anniversary of Pig Days (2014)
 * Thu. 30 July: Release of Angry Birds 2 (2015)
 * Sun. 02 August: World Friendship Day (1958)
 * Sat. 08 August: World Cat Day (2002)
 * Tue. 11 August: Play in the Sand Day (?)
 * Sun. 23 August: Ride the Wind Day (?)
 * Sun. 30 August: International Bat Night (?)
 * Tue. 08 September: International Literacy Day (1967)
 * Thu. 16. September: Preservation of the Ozone Layer Day (1995)
 * Tue. 22. September: Car-Free Day (1990s)

Chapter 5: v5.3.1

 * Thu. 22. October: 5th Anniversary of Angry Birds Seasons (2010)
 * Thu. 29. October: World Internet Day (2005)
 * Mon. 02. November: All Souls' Day (circa 4th century)
 * Wen. 11. November: Origami Day (?)
 * Tue. 17. November: Meteor Shower Day (first recorded 902)
 * Tue. 31. December 2015: New Year's Day (2016)
 * Sun. 10. January 2016: Crossing the Rubicon Day (49 BC)
 * Wen. 20. January: Penguin Awareness Day (?)
 * Mon. 08. February: Chinese New Year, Year of the Monkey (?)

Chapter 6: v6.0.0

 * Sun. 14. February: Valentine's Day 2016
 * Sun. 28. February: World Polar Bear Day 2016
 * Wen. 02. March: World Wildlife Day (2013)
 * Mon. 07. March: Women's Day (1909)
 * Tue. 08/09. March: Solar Eclipse (2016)
 * Fri. 18. March: Earth Hour (2007)
 * Sat. 26. March: Easter 2016

Chapter 7: v6.0.1

 * Fri. 01 . April : April Fools Day, spoofed as International Pig Acceptance and Appreciation Day (1392)
 * Sun. 10. April: Golf Day (?)
 * Tue. 12. April: First Spaceflight 2016
 * Thu. 21. April: Loch Ness Monster Day (?)
 * Sun. 24. April: World Penguin Day (?)
 * Sun. 08. May: Mother's Day (1908)
 * Thu. 12. May: Anger Management (promotion for The Angry Birds Movie, 2016) 
 * Fri. 13. May: Pigs Arrive (promotion for The Angry Birds Movie - day of most international releases, 2016)
 * Fri. 20. May: The Eagle's Den (promotion for The Angry Birds Movie - China, United States, Canada releases, 2016)
 * Sun. 29. May: Everest Day - first ascent of Mount Everest by Tenzing Norgay and Sir Edmund Hillary (1953)
 * Wen. 01. June: World Milk Day (2001) 

Trivia

 * On the Pig Days map, a mooncake with a candle is shown, for the 4th anniversary of AngryBirdsNest.
 * It is the second game that a Fat Pig appears outside of "Angry Birds Space" and the third appearance of "El Porkador!".
 * It is the second game to have alliteration in the background levels.
 * Ever since the Summer Camp update, Pig Days is located in the 2016 section, shows how many stars, coins, and feathers the player has achieved, and hasn't had a new level added since World Milk Day, indicating that it has ended.
 * This is the longest episode ever released in the entire Angry Birds series with 93 levels. The second is Poached Eggs with 63 levels, which is 30 levels behind.

New sprites and features
The Pig Days introduced some new sprites and/or features in Angry Birds Seasons:
 * 1-1: Fire sprite. It used later in 1-7.
 * 1-2: Wingman and El Porkador came from Angry Birds Friends, but Wingman lost his 'WHAM!' figures. - The 'ComPigCon' and 'ComBirdCon' posters. - Terence also equipped with a hard ball, chained to him.
 * 1-6: Clouds now are 'out of the background' and can block your way.
 * 1-8: Basketball and net. It used later in Ham Dunk episode, alongside net stander and and 'Dunk' bonus.
 * 1-12: Barad-dûr Tower sun sign and flag.
 * 2-2: Zombie pig costume.
 * 2-5: Guy Fawkes clothes for pigs.
 * 2-6: Minion Pigs are Playable, Cannons and Swords
 * 2-8: The explosive King Pig golden sign.
 * 2-9: Feathers and turkey skin.
 * 2-12: Alien pig costume and floating object. It used later in Invasion of the Egg Snatchers episode.
 * 2-13: Rubber Duck. It used later in Angry Birds 2 as Power-Up.
 * 2-14: Popcorn and Shovel.
 * 2-15: Fuse, Pickaxe, Scarf and Stop sign.
 * 3-1: Big Red Ballon
 * 3-2: Tennis Racket, Tennis Ball and Rio Open banner sign
 * 3-5: Space Helmet and Wrench
 * 3-10: Pepper
 * 3-11: Windmill
 * 3-12: Hats and Cow costume.
 * 4-1: Wigs
 * 4-2: Newspaper
 * 4-3: Fish
 * 4-9: Straw House
 * 4-10: Devil Rubber Duck
 * 5-7: Origami
 * 5-9: Big Glass
 * 5-10: Straws
 * 6-2: Warning block.
 * 6-12: Wig