Taming animals could be a new technology of tier 2 or 3. Would be allow just common animals like chiken so you can tame some chiken and put inside the wall to produce some egg (1-3 egg by 1 hour) or a wolf to protect you like a pet in battle.
And of course you would need some material to do those taming like food + something depending of the animal.
Proposed chicken coop technology level 2 agriculture
building size: 2 fields for 3 fields
Construction recipe: 100 eggs + 200 cereals + 100 bottles of water
work: 4 hours requires 10 grains + 1 water in a bottle
returns 1 empty bottle 1 egg