Here is the full list of all 31 Chicken Police achievements.
Get the secret ending!
Disturb Bloodbolye's peace at least three times
Get all personal informations
Complete all the questionings with "Living Legend" results
Finish the game with 0 failed questionings
Find all 10 Chicken Police novels
Get all the collectible extras
Die at least 3 times on the burning ship
Get a "Living Legend" grade on a questioning
Get a "Frank Drebin" grade on a questioning
Get all the 58 art gallery pictures
Get all the cutscenes of the game
Reach the ending
Complete chapter four
Get to the point where Natasha kills Albert Wessler
Talk with all the characters in the game
Visit all the limited locations
Talk to Marty about his feelings before confronting Wessler
Get all codex entries
Talk to Marty about the case that separated the Chicken Police
Talk with the "super-fan" nurse at the asylum
Complete the third chapter
Kill the 2 lights of the enemy car in one of the car chase sequences
Collect all the songs for the jukebox
Help Mort get a room for the night
Complete the second chapter
Complete the first chapter
Ask Natasha about Ibn Wessler in her room
Steal that fancy whisky from the Czar Club
Visit the Hop-Dog after the first Police scene
Score at least 5000 points at the shooting range