Animal escape artists..

[Thalius]

We are seeing a LOT of our sheep and pigs escape from fenced in and even walled in enclosures.  We have tried double high fences and have had players set a second ring of fencing around their main corral (with several tiles of space in between the inner and outer fence perimeters), and pigs are found outside the main enclosure but within the second outer fence line, clearly showing that they are somehow "phasing" through fencing and escaping their pens.

Our server reset with the release of client version 1.15.5, and we are just, within the last few weeks, getting to significant populations of domesticated animals.  We saw a few go strangely missing all along from time to time, but now that populations are higher we are more able to tell what is going on, and we are seeing it a lot.

Trying to discern if a mod might be causing this, but we have no mods enabled that mess with fencing or collision mechanics or other such things. No clue what is allowing this "phase" glitch to happen.

Are we alone in seeing this? If so, it is likely related to some mod or other server specific issue.

Thanks in advance...
~TH~

Edited September 14, 2021 by Thalius

[Streetwind]

- Make sure your enclosures are large enough so that animals do not push into each other. In my experience, the larger the enclosure, the fewer animals phase through fences. It's by far the biggest contributing factor.

- Avoid building your fence across changing elevations. Even if you terraform nothing else, try and make your enclosures flat.

- Do not have filled troughs on the other side of fences. Sometimes, an animal will decide that it absolutely must eat from a trough outside of its enclosure, and will throw itself against the fence until it eventually glitches through. Happens a lot to people who like to make enclosures for different animals all next to each other. Troughs have a certain range; try to make sure animals can only detect those they can reach.

[Onsdag]

We see this happen on our server too (1.15.3 currently, but has also happened for 1.14.10). No mods; just vanilla.

Best I can tell it usually happens soon after the animals give birth and/or reach maturity and there is a 'growth' explosion. Not all the animals can fit comfortably in the pens and it seems to pop some of them outside the enclosure.

[Thalius]

Appreciate the feedback and the pointers.

We have a few pretty experienced players in our crowd and have discussed these things and how much they may be playing a role in the problem. It just seems like it is happening a LOT more than it usually did on our previous server and on other servers our folks have played on in the past.  We were wondering if we are the only ones that have seen an increase in this happening.

[Windego]

I can attest it's happened to me quite often in most if not almost all playthroughs and different versions of the game. New saves, old saves, migrated saves.. And both @Streetwind and @ Onsdag have extremely valid points. I've personally seen all mentioned reasons above, being a potential cause and have even seen it happen in person. What also happens, when you have your pens placed in the boarders of chunks, where they connect, some animals will clip through the fences as cause by leaving and entering the other chunk adjacent to the one they're leaving.
I suspect it'll be fixed eventually, but there are a few things including the ones mentioned above, that you could do to prevent it. At least to some degree.
Given you're familiar with the wireframe debug command, I'd suggest toggling it on and see if the pen is in several connecting chunks.
I hope the information helps a bit as I was troubled by it as well for quite a long while.
Cheers!

[Fancygoat]

I have experiences something similar in my single player world, but with me it seemed to happen with gates. I even watched it happen, pig sleeps right up to gate an phases trough as if the game reads the gate as open although it is closed. I now have enclosures without gates an my animals do not escape anymore, even if they are tightly packed together. (also use dobble height fences and have flat ground inside the enclosure)