When you build a stall inside a pasture, does the pasture split, and what happens to the square underneath?

Question

Accepted Answer

The square with the stall stops being part of any pasture and becomes the stall, so the remaining open squares form the pastures. A stall in the middle of a 1x3 pasture leaves two pastures plus the stall. A stall's own yellow borders mean it can never join a pasture.

Agricola: All Creatures Big and Small

When you build a stall inside a pasture, does the pasture split, and what happens to the square underneath?