Is there a difference between horizontal and veritcle nipples, or is it just the placement? I would think they'd both be the same, but not quite sure.
Hey there lereg15:

1. Because the birds don't have water dripping in their face and nostrils from drinking above their heads.
2. with the horizontals I can place the bucket on a platform on the ground or suspend from above... nice if your coop is "vertically challenged" (not high enough inside to hang the bucket from the ceiling)
3. The horizontals have a little "cup" like protrusion under the nipple mechanism to kind of "hold" the water coming out rather than it just being a drip/dribble falling out of the nipple. I thought it made sense and would make it easier for the birds to drink from.
4. The birds can drink from a more natural angle by adjusting the height of the water source (bucket/pvc pipe).