Heating pad

An animal containment pen comprising a floor on which the animal can stand and a heating pad for providing heat to an animal in the pen, the heating pad being loosely laid on top of the floor so as to be seperable therefrom, the heating pad comprising a substantially planar body having an upper substantially flat surface and a lower substantially flat surface for resting on the floor, and means within the body defining a continuous channel for passage therethrough of a heating liquid, the channel having inlet means connected to a source of heated liquid, outlet means connected to a drain for the liquid and a single continuous duct extending from the inlet means to the outlet means and means forming the duct into a convoluted path having a plurality of convolutions lying in a substantially common plane within the body, said body comprising a means defining a substantially planar upper sheet, means defining a substantially planar lower sheet parallel to the upper sheet and spaced therefrom to define a hollow interior therebetween within which said duct extends, the lower sheet being shaped to define a plurality of upwardly projecting support bodies, each support body comprising a top wall, arranged parallel to and in contact with the upper sheet to provide support therefor, and side walls means connecting the top wall and the lower sheet, the side wall means and the top wall being formed by deformation of a portion of the lower sheet upwardly from the plane of the lower sheet, said duct comprising a tube wrapped around at least some of the support bodies so as to be configured into the convoluted path by contact with the side wall means thereof.