Horizontal nipples are made for the shape of the beak. The bottom of the nipple conforms with the shape of the bottom beak. When the chicken pushes on the nipple a little bit of water is deposited in the bottom beak. If you put the nipples down at nearly floor level the shape of the nipple and the shape of the beak won't match up. It's not like getting a drink of water from a pool of water where they put their beak in and are able to scoop the water up. There is no scooping up with a horizontal nipple. Horizontal nipples should be up about head high.