Minecraft wiki entry for Chicken_Jockey, associated text: 0–2 rotten flesh, and rarely carrots, potatoes and iron ingots.
Baby zombies also have a 8.5% chance each of dropping their
Iron Shovel
Iron Sword
or any equipped armor that they spawned with. The chance of each can be increased by 1% per level of Looting, up to 11.5% chance. The equipment is usually badly damaged, and may be enchanted.