The assemblies of the invention are suitable for mounting to, or being an integral part of, an animal enclosure such that the height of a valve-controlled liquid outlet may be adjusted according to the changing needs of growing animals. The adjustable liquid delivery assemblies comprise an elongated rail, a liquid delivery unit having at least one liquid delivery head slideably engaged with the elongated rail, a flexible liquid delivery tube for connecting a liquid delivery head to a liquid source, and a means for securing the liquid delivery unit at a selected position on the elongated rail.
