Livestock keep jumping over the fences, placing half-slabs on top of the fences makes it better but doesn't stop the problem at all.
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LOL Thanks Grum! But I still hope you can work around this problem for future updates! Cheers!

I think it's more apparent on sheep, they can escape through fences but wasn't this fixed?

Actually I've been having more trouble with pigs jumping over. They did fix it a long time ago but it never worked at a 100%, but it used to be a lot worse, and I'm guessing that with the tweeks they've been doing lately, maybe something got messed up with the code again.
Workaround: Dig one down, place fence on the edge. They can bunch up and jump of eachother 😛