As usual, I don’t know it’s necessarily a bug, but it was certainly a rude surprise.
I tried making a Sheep area 9 by 16, and couldn’t set the space because of the lower limits in place. Apparently the sheep area must be at least 10 by 10 to be set.
How about a lower limit of 4 by 4? Or 5 by 5? That should be big enough for at least a single sheep, at least.