Horizontal nipples:
These release water as chickens peck at a stainless steel section. The chickens soon pick up how to operate this system and it is both very clean and very durable. If you knock your waterer around in your ute tray this is the option for you. These are best suited to chickens, guinea fowl, and quail. Poultry learn this system quickly.
Automatic cups:
These cups are larger and self fill. Water sits permanently in the cup. There is no need for pecking to activate water. These are suited to a wide variety of animals including all poultry, waterfowl, aviary birds, cats, small dogs, and wildlife. These cups are also great for insects and lizards in your garden. If you have ducks or silkies (chickens) I would highly recommend these cups.