The cockatrice is listed as a grassland creature in the monster manual. That feels a little odd as the cockatrice is slow on the ground (20 feet). They are good fliers, but I like the idea of adventurers stumbling into a colony of cockatrices, maybe as a random encounter.
Here’s a stat block for the cockatrice from the Basic Rules:
It seems like cockatrices maybe have a similar social structure to mundane chickens that have gone feral; they live in a group. Their reptile nature and plains environment make results in them living in subterranean burrows. There are probably a few large chambers where the cockatrices roost connected by a network of tunnels. The cockatrice is small, and the tunnesl should match it’s size, making it so that only a few adventurers can comfortably enter their home.
Likely there would also be a few victims scattered around the area, as statues. It also seems likely that some of these may have succumb to petrification. The petrification only last for 24 hours, so that would likely limit the number of petrified victims.
This encounter can be used as a random encounter, or as a side quest. Hide enough cockatrices in the brambles to make a hard encounter for your party. Choose a magical item that would be a good reward for their efforts.
As the party travels, they spot a patch of bramble at the edge of a stream. In the center of the patch, there is a stone statue. It stands in the middle of the brambles, only head and shoulder visible above the thorny branches. The statue has one fist raised above its head.
The bramble is difficult terrain.
- A successful nature or survival check will reveal that the brambles are difficult terrain, and that they are blackberries.
- A successful investigation check will reveal that the that the statue is wearing a peasant’s clothes. Something shiny is gripped in its hand, held up over its head.
- A successful perception check with reveal that some small creatures are moving among the brambles. They are staying out of sight…
What happens next:
- If the party walks away, nothing happens. Later, when they are in an in or town, they will overhear a commoner talking about how they were petrified by some cockatrice, but it only lasted so long. When the petrification ended, he was able to sneak out of the bramble with a very special object he found there…
- If the party or any of its members enter the brambles, the cockatrices attack. They have partial cover while in the brambles and will not leave the brambles to attack. They also have burrows and will withdraw to the burrows. The brambles are difficult terrain only for creatures larger than small, and so the cockatrices are able to move freely. The Cockatrices will only attack party members as long as they are within the brambles.
- The party may choose to attempt to carry the statue out of the brambles or just take whatever is in the statues hand. The statue weighs 260 pounds. Check their carrying weight.
- The party may choose to remove the magic item from the statue’s hand. Doing so will break the hand of the statue. They will later encounter a commoner who tells the tale of the time they were petrified by cockatrices and woke up with missing a hand.
- Any members of the party that are turned to stone return to normal after 24 hours. The statue in the bramble will revive and leave before them. The next time the party is in an appropriate setting they will encounter a commoner who recognizes them.