Fences aren't holding in cows, chickens, pigs, and sheep.

I have a large farm with sort of cages made for fence for cows, sheep, pigs, and chickens. I make sure they 100% can not get out by somehow getting over the fence and escape yet they somehow get out. they will be pressing themselves against the fence itself just staring outside, twisting around from time to time like thy're stuck in the fence the poof they're outside of their pins. It's very annoying and is especially bad with chickens and pigs. It only seems to happen to those four mobs thankfully but it make my farm ineffective as all my livestock gets out and runs away.