The number of villagers in the village must be under 35% of thenumber of doors in the village, for them to even attempt to breed.So a village with 100 valid doors, can support a village populationof 35 - if the population is below this, it is possible for them tobreed.But it is not as simple as that, as villagers must also bewilling. They can be made willing by completing trades with them,and they will become willing if they have a certain amount of foodin their hidden inventory - 3 bread, 12 carrots and 12 potatoes.Villagers will harvest the village crops, craft bread and sharefood to help facilitate breeding.