Evoland Legendary Edition

This is unlocked in Evoland II.

You'll find Cluckety Isle in the northeast on the world map in the Future. You'll need the Flying Machine to reach it.

It's a simple small island that only appears to have a single chicken and a chest on it. Once you attack and kill that chicken, you'll get attacked by a large group of chickens a la the Legend of Zelda that you will have to defeat. It's pretty simple, but be aware the chickens do a very large amount of damage per hit.

The achievement will pop once you kill the large group. A small piece of bridge will also appear after defeating them, allowing you to cross to the treasure chest, which contains a piece of Orikon Ore.