Hunt zombies or zombie hens
This new Halloween event challenge simply asks you to eliminate various creatures. Here you have the choice between simple zombies, or zombie hens.The first ones, the zombies, can be found, among other places, in Grim Gables. The other choice, zombie chickens, are much more numerous on the battlefield, since we find them in the southern part of the island, and also in the surroundings of Lustrous Lagoon. You just have to go to one of these areas to complete the challenge. In general, two pickaxes or two bullets, depending on the weapon and the rarity, are enough to eliminate your target.

Note that you will have to eliminate a total of five zombies or zombie hens to unlock the reward, namely 15 XP, for your Battle Pass.
You can find all Fortnite Nightmares challenges in this guide.