Passive mobs drop no loot

I went to a Bandland to find the new armadillo. When I got there, my brush broke and I had no spare on me, so I went to kill some chickens to craft a new brush. The problem I experienced was that they dropped no loot at all, whether it's food or their other loots. I also tried pigs and cows to see, and they have the same issue. I have a Netherite sword with Looting 3 and nothing happened.