Chickens stuck in stone wall

Put the summary of the bug you're having here
(The version is actually 0.8.1 but the site wouldn't let be select that)
What I expected to happen was...:
Chickens roam around freely inside my stone walls

*What actually happened was"
Chickens tried jumping over, (while unable) and when they landed their jumps they get stuck inside the stone wall, unable to move unless I push them out.

Steps to Reproduce:
1. Make an enclosed stone wall area, with a chicken inside the walled interior.
2. Chicken will try to occasionally jump over the walls, while being unable because they are designed like fences.
3. When rage quitting because of their inability to jump over the wall, they will be stuck inside the wall. *note: they only seem to get stuck in the joints of the stone walls.