Which of the following is not required to be available in an avian hospital ward?

The correct choice is "spacious" because, while having adequate space is beneficial for the well-being of birds in an avian hospital ward, it is not an absolute requirement like the other listed factors. A quiet environment is crucial for reducing stress and anxiety in birds, as they are particularly sensitive to noise and disturbances. Temperature control is also essential to ensure that birds maintain their body temperature, as many species require a warm environment to feel secure and comfortable. Additionally, some birds may require a darkened area for resting and recuperation, as darkness can promote a sense of safety and encourage natural behaviors.

While a spacious environment can support birds by allowing them to move freely and reduce stress, it is possible to provide care in a smaller area if the other conditions—quiet, warm, and dark—are adequately met. Thus, while spaciousness is ideal, it is not strictly necessary for every avian hospital ward.