my animals disappear and I don't know why, my sheep, cows, even my horse disappeared and all of them were locked up and there was no way to escape

This happened to me many times and i was so upset cause i always lost
my armored and epic horse...even my villager
disappeared

Animals despawn just like monsters, unless you give them persistence by tempting them with food or breeding them. Had you done either of these things?

Cleaning up old tickets: This ticket had been set to 'Awaiting Response', but has not received a response from the reporter (~3 months+) so is being closed as Incomplete. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines which includes steps to reproduce the problem.

Quick Links:
📓 Issue Guidelines – 💬 Mojang Support – 📧 Suggestions – 📖 Minecraft Wiki