Fenced Animals Disappear When Game Offline

Cows, sheep and chickens are fenced. While playing, they don't despawn. After leaving the realm and coming back, a random number of animals will disappear. It's super frustrating as we have bred upwards of 10 and come back to all of them missing multiple times. We are desperately trying to get leather to progress the realm but it's almost impossible when the animals keep disappearing.