No, but someone else did in reply. Sorry to be fair your post specifically DIDNT mention bug so shouldnt have got on my high horse. Just a pet hate of mine.
I said it...and it's true, there's currently a bug that causes animals to pass through barriers, and even terrain, in order to escape an enclosure that is perfectly enclosed for them. Click the link I posted for some very obvious screen captures that show it.
But in this case, yah...it's not that bug, it was user error. Which happens all the time too. I had all my baby Ostriches escape just last night because I had placed a mud bath which I didn't realize raised the terrain just a tiny bit next to the barrier near where it was placed, and they all were able to jump out. :-(