Why am I unable to breed villagers in my setup? (1.8.8)

I’m currently trying out villager breeding, and it’s been an hour of me afking and hasn’t gotten any new villagers (I started out with 6) l. They are in a room that’s 19×19, and I am wanting to know if such a thing as “too big of a room” is possible for them to breed. There’s doors on 3 of the walls and there’s wheat on almost all the floor of the room, with a 2 block tall pillar over each water source block with torches (there’s 9 water source blocks). Is there anything I’m doing wrong? Any advice will be appreciated