On recent snapshots the animals die from Suffocation, they are not despawning, they just die, when you save and quit and then return the enclosed animals sink on the ground and die after some seconds, it's a similar bug but i don't think is the same issue as this one.
On recent snapshots the animals die from Suffocation, they are not despawning, they just die, when you save and quit and then return the enclosed animals sink on the ground and die after some seconds, it's a similar bug but i don't think is the same issue as this one.