A barrier comprises at least one grating comprising a plurality of elongated openings; a winch positioned above the at least the one grating and rotatable between first and second positions; and at least one cable connected at a first end to the winch and at a second end to the at least one grating, the at least one cable holding the at least one grating in an upright position on a support surface when the winch is in the first position and lifting the at least one grating from the support surface towards the winch during rotation of the winch from the first position to the second position.

A stand-alone chamber or multi-chamber inhalation system has at least two alternative vaporized test liquid supply systems for passive or self-administered delivery of vaporized test fluid and air to one or more test chambers, which can be passive or restraint chambers, based on operator selection of delivery on and off times in a passive mode or actuation of an actuator in the chamber by a test animal in a self-administered mode. In one case, a multiple inhalation chamber system has two or more separate test fluid delivery systems and provides options for selective passive uniform drug delivery to multiple chambers or selective delivery of two or more different drugs to different groups of chambers from different delivery systems so that two different drugs or different concentrations of delivered drugs can be tested simultaneously.

An improvement for an animal cage is disclosed. The animal cage may include a first, second, third and fourth vertical wall, each of which is connected to a floor on a first end and includes a top rim opposite to the first end. The improvement includes a support structure and a removable divider. The support structure includes at least one slot, is positioned above the floor and may be connected adjacent to the top rim of the first and second vertical walls. The removable divider is inserted into the slot and extends vertically away from the floor. A snap-fit connection detachably connects the divider to the support structure.

A horse pen bar system, configured for installation within an entrance of a horse pen for containing a horse and improving the psychological well-being of the horse. Wherein: the horse pen bar system comprises a main support bar and two threaded assemblies. The main support bar extends longitudinally between the two threaded assemblies. The two threaded assemblies comprises a first threaded assembly and a second threaded assembly. The two threaded assemblies are positioned at opposing ends of main support bar. Each of the two threaded assemblies includes a threaded shaft and an engagement element. The entrance defines the open area between two vertical supports. The two vertical supports comprise a first vertical support and a second vertical support, positioned on opposing sides of the entrance. The threaded shaft enables length adjustment through rotational movement, allowing the horse pen bar system to fit securely within the entrance.