Angry Birds Seasons/Unused Content

Angry Birds Seasons is the second Angry Birds game to be released and it got a lot of unused content as seen below:

Scientist Bubbles
An unseen Bird Wear appears in the preview for the Bird Wears, it's the Scientist Bubbles costume. It isn't obtainable in the game by any sort. It could possibly be a beta design for Bubbles's Hulk Costume.

Year Of The Goat
In the files, there is a sprite for a button of the episode Year Of The Goat that is not used in the game and was probably meant to be released on the start of 2015, since this was the latest Year Of The Goat and it uses the Classic Designs. While not used in the game, a Chinese Version of Angry Birds Classic features this episode fully playable.

Animals Pig Days Level
In the files for the Pig Days level icons, there is an icon of a penguin, polar bear, fish and bat which could be for either World Animal Day, or any other environment day.

Alien Pig Brain
In the files, there are sprites for brain costumes for the pigs which could appear in the levels, one has its brain fully showing intended for large pigs while there's another where the brain is almost visible, intended for medium pigs.

Unused Names
There are some names that weren't used and are different or placeholder name the developers made.

Eggs Files
In the files, different from other episodes that have their theme as name, the assets for Invasion of the Egg Snatchers have the name Eggsfiles, a initial name for the episode that uses a pun on X-Files but they probably didn't use this name because it doesn't make so much sense.