My villager breeder won't work. I've made a villager breeder and I have about 8 villagers in it, I've fed the villagers with a few stacks of carrots, potatoes, beets and bread. The villagers are displaying heart particles but don't produce baby villagers. I have one bucket of water on the ground below streaming the villagers into a trading station (obviously there are no villagers to stream) and I was wondering if this prevents the villagers to breed (like other mob spawns).
Water on the ground does not prevent villager breeding.
The fact that you have hearts means the villagers are willing to breed. Unlike some of the animals, when villagers display hearts, they don't immediately seek another to mate with. They take their time. Even when two villagers are looking at each other, both with hearts, they don't always breed.
You probably just have to wait for them to breed. One thing to check for, make sure that you are not just accidentally suffocating/killing the babies.