Passive mobs just vanished

I was feeding a big group of pigs like 40-50, and instead of jamming around me they fused on one single pig, i was still able to feed them and hearts still appear but no babies or exp and then they all vanished including the cows, chickens, sheeps and like 1/4 of my villagers but not the nearest villagers to my position neither the farthest but the ones on the middle.

One skeleton was near and he still on the game, so i believe that the problems is only with the passive mobs?

On the pics: the one with glass was the chicken area, the holes in the dirt the pig and cow area, some villagers that are still here and some that are gone.