I reduce villager population in village,(To reduce lag of my device due to more entity cause memory usage) by burning it and trapping. But reducing villager in village will villager breed again to make baby villager? It is match the number of wooden doors? Because i'm scared that if i decrease villager, may cannot breed again.
But they only breed if they have food or if you trade with them.
If there are farms and at least one farmer type villager (any profession with a brown coat and no apron) they should harvest crops and throw some at any villager they come across that doesn't have enough, otherwise you have to trade or toss food at them.
Killing off unwanted/excess villagers directly (eg with a sword) will negatively affect the player's popularity score (stored seperately for each village).
'Arranging "accidents"' (eg nudging a villager off a cliff or placing a lava block nearby) does not incur this penalty.
But, "If a villager dies to a non-mob, non-player source while a player is within 16 blocks (spherical radius), or if a monster kills a villager, then no villager in the village will mate for approximately 3 minutes"
After that, however, villagers with sufficient food will again begin breeding until the village population is equal to (or just under) Number_of_Doors * 0.35
Unfortunately, villager information is rather scattered on the wiki. The following pages may be of interest: