Is there a bug with friendly mobs. I am losing all mine sheep, cows, pigs, and some villagers. I had them all penned in, walked 50 blocks away and when I came back they are gone.
Is that for the wastelands or frontier or both? Than what good would building a base in frontier be if all your animals always despawn?
No animals do not auto despawn in wild. It is possible you had over 250 in the area and it caused them to despawn due to being over the limit?