This problem has been happening forever and still no fix I'm so sick of this game because you people don't know how to fix simple problems you make me sick!
There are ways to mitigate this. What exactly are you experiencing?
I keep 38 in a 1 x 1 cell in my iron farm reliably.
Most times keeping glass or fences at head level will solve any problems. If the problem is escaping then make sure the corners are filled.