Hello great to hear you are loving the game! That is actually Ol' Popahkays Hut, a Legendary Witch Chook that was temporarily available in the game for a Halloween event along with a few others.
The bad news is we had to ditch the idea of timed events.
The good news is we came up with something much cooler, which we are currently working on and going to release real soon. :D
If you join our Discord we make announcements about updates, and other cool Chook/Trilum related goss. :D