Items, NPCs, quests, objects and spells of patch 1.12.1, read live from the realm itself.

Chicken Egg

NPC Level Zone Chance

Harvest Watcher 14 - 15 Westfall 0.02%

Mangy Wolf 5 - 6 Elwynn Forest 0.02%
Object Zone Chance

Farm Chicken Egg 100%

NPC	Level	Zone	Chance
Harvest Watcher	14 - 15	Westfall	0.02%
Mangy Wolf	5 - 6	Elwynn Forest	0.02%