A twitch sims 4 streamer mentioned the evil chicken challenge on one of her streams. So I looked it up on Google:
The "evil chicken challenge" is a community-created gameplay concept in The Sims 4 that typically involves the goal of raising a specific number of evil chickens or building a scenario around them, utilizing features from the Cottage Living Expansion Pack.
How to Get an Evil Chicken
To get an evil chicken, you need to acquire an Obsidian Egg or feed an existing chicken a Midnight Treat.
Obtaining an Obsidian Egg
Relationship Status: Hens that are very happy but have a bad relationship with their owner have a chance to lay an Obsidian Egg.
Treats: Feeding a chicken a Spicy Treat can result in a hatchable Obsidian Egg.
Hatching: Place the Obsidian Egg in a chicken coop to hatch an evil chick, which will grow into an evil chicken.
Using a Midnight Treat
Purchase: Midnight Treats can sometimes be purchased from the garden stall in Henford-on-Bagley or a grocery delivery person.
Crafting: Midnight Treats can also be made using a Cowberry Jam and an Obsidian Egg.
Feeding: Feeding the treat directly to a fully-grown chicken will turn it evil.
Evil Chicken Abilities
Protection: You can ask an evil chicken for help to protect your home from foxes, household enemies, vampires, and even the Grim Reaper. They can get into a fight loop with the Grim Reaper, potentially preventing a Sim's death.
Laying Eggs: Happy evil hens will always lay Obsidian Eggs.
Mean Interactions: Performing multiple mean interactions on a chicken can provoke it into attacking, which can even result in a Sim's death if you push it too far.
Challenge Ideas
While there isn't one official "evil chicken challenge", players have created various scenarios, such as:
The 100 Chicken Challenge: A variation of the 100 Baby Challenge, focusing on raising 100 chickens, including evil ones.
Rags to Riches: Incorporating evil chickens and their unique eggs into a rags-to-riches storyline.
Evil Lair: Building a specific area or "island" to contain and manage a collection of evil chickens.
I am in the early stages of playing this myself and am finding it alot of fun. Maybe this would be an idea for gameplay?