Villages spawn too many villagers!

Villages that spawn with small houses always spawns farmer villagers (brown coated villagers). Also in one of the houses they spawn more than they should. For example: in the butchers' house they spawn 3 villagers instead of 2. The number of farmer villagers that farm during the day cause a lot of lag which reduces a LOT of fps. I think this should be nerfed down despite the fact when its combined with a mineshaft its barely playable. Also they also get stuck on the roof somehow, for this I do not know the reason why this happens.