An at least partially open sided outdoor animal shelter structure 20 to condition animals when positioned within the structure 20, to a desired physiological state by controlling the environment in the structure, the structure including a floor 2 to support animals, side supports, a water impervious canopy 22 supported by the side supports, the canopy 22 being supported above at least part of the floor 2, the canopy 22 allowing at least some ambient light to pass through and into the structure 20, an environment modification means to allow a change in the environment any animal on the floor 2 will experience, the modification means comprising movable shade cloth 30, that in one position is located intermediate of the canopy 20 and the animals when any such are located in the structure 20.
