[SuperCreeper007]

I had another problem with my farm, though. It's completely fenced from all directions, even above, but when I went to check on the next day after that, there was a wolf inside the pen, and all except one of my sheep were gone. The wolf could only have spawned there, as it was completely blocked off, so how do I stop this?

If it's blocked off in every direction, the wolf could not have spawned in the room. All animals spawn on the highest available block in a column. The wolf must have glitched in.

Thanks. So this was like a one in a million occurrence? Or do the fences that were on top of the sheep not counted as blocks in the column?