The documents are a bit broader, encompassing other platforms’ Chicken Run games (including an unreleased GBA title).
CodeBound released the source code, development documents, and 52 prototypes for Chicken Run on GBC
Submitted 9 months ago by Rockafeller@preserve.games to gamehistory@preserve.games
https://archive.org/details/chicken-run-gbc-source-code-sep-7-2000