I have a barn that occupies a space of 1 chunk. I had 2 each of chickens, cows, sheep and pigs in there. Trying to breed them mostly failed entirely (I managed to get 1 more chicken and 1 more pig in 4 breeding attempts of all types of animal), and then after server restart all of them were gone. I also have found that several of my chocobos vanish if I leave the chunk and come back - at maximum I had 12 wandering my base, came back to find only 5 remaining. There are no other passive mobs around my base, and I kill all the aggressive ones that come close too, yet my animals keep vanishing.
I'd build a Magnum Torch (from extra utilities) to eliminate any aggressive mobs in the area and try your luck then. Make sure you also have a chunkloader running to see if that'll help. Believe it was that at most you can have 30 mobs (aggressive and passive) in a 3x3 chunk area.
I really don't have the ability to make a magnum torch right now, those things are expensive, especially when you need the QED to be able to make them in the first place! 30 mobs total limit in 3x3 chunks seems really low as well, especially since you can't control stuff like bats spawning in caves below... I get that there's a reason for it, but still...[DOUBLEPOST=1476807947,1476807010][/DOUBLEPOST]Also, it looks like new mobs wanting to spawn have higher priority than existing ones, if mob cap is the reason my animals are vanishing - or at the very least, aggressive mobs wanting to spawn have higher priority than existing passive ones. Which seems kinda wrong to me, especially in a pack that has mods like Chococraft, where you can invest quite a lot of time in breeding the creature you want - for it to then disappear because a zombie is due to spawn 2 chunks away is very upsetting.
I also agree on the part of the mob limit being too low not to mention if you are using something like thaumcraft you can lose your golems when trying to place them down (happend to me 6 times)
Our server side mob limiting plugin is to blame. Maybe we could see about increasing it as the TPS has been pretty good lately.
It has also happened to named and saddled horses in our claim (and in a pen). I thought named animals were never supposed to despawn.
They do not despawn persay. What happens is that when a chunk unloads, minecraft saves all entities that were in the chunk. On chunk reload, it spawns them back in. If, when it gets to your named animal, the mob cap is already reached then your named animal will not spawn in.
